Merged branch 'jetty-10.0.x' into 'jetty-10.0.x-convert_synchronized_to_autolock'.

VERSION.txt

@@ -1,6 +1,31 @@
 jetty-10.0.0-SNAPSHOT
 
-jetty-10.0.0.beta0 - 27 May 2020
+jetty-9.4.31.v20200723 - 23 July 2020
+ + 1100 JSR356 Encoder#init is not called when created on demand
+ + 4736 Update Import-Package version start ranges
+ + 4890 JettyClient behavior when SETTINGS_HEADER_TABLE_SIZE is set to 0 in
+   SETTINGS Frame.
+ + 4904 WebsocketClient creates more connections than needed
+ + 4965 WINDOW_UPDATE for locally failed stream should not close the HTTP/2
+   session
+ + 4967 Possible buffer corruption in HTTP/2 session failures
+ + 4971 Simplify Connection.upgradeFrom()/upgradeTo()
+ + 4976 HttpClient async content throws NPE in DEBUG log
+ + 4981 Incorrect example for TryFilesFilter API docs
+ + 4985 Fix NPE related to use of Attributes.Wrapper getAttributeNameSet()
+ + 4989 Prevent parsing of module-info.class in OSGi bundles
+ + 5000 NPE from Server.dump of FilterMapping
+ + 5013 Bundle-ClassPath and lib place on WEB-INF/lib make classpath duplicate
+ + 5018 WebSocketClient connect / upgrade timeout not configurable
+ + 5019 Automatically hot-reload SSL certificates if keystore file changed
+ + 5020 LifeCycle.Listener not called for Filter/Servlet/Listener lifecycle
+   events
+ + 5025 dispatcher.include() with welcome files lead to stack overflow error
+ + 5053 CWE-331 in DigestAuthentication class
+ + 5057 `javax.servlet.include.context_path` attribute on root context. should
+   be empty string, but is `"/"`
+ + 5064 NotSerializableException for OpenIdConfiguration
+ + 5069 HttpClientTimeoutTests can occasionally fail due to unreachable network
 
 jetty-9.4.30.v20200611 - 11 June 2020
  + 4776 Incorrect path matching for WebSocket using PathMappings
@@ -48,361 +73,6 @@ jetty-9.4.29.v20200521 - 21 May 2020
  + 4895 AbstractSessionCache.setFlushOnResponseCommit(true) can write an
    invalid session to the backing store
 
-jetty-10.0.0.alpha1 - 26 November 2019
- + 97 Permanent UnavailableException thrown during servlet request handling
-   should cause servlet destroy
- + 137 Support OAuth
- + 155 No way to set keystore for JSR 356 websocket clients, needed for SSL
-   client authentication
- + 250 Implement HTTP CONNECT for HTTP/2
- + 995 UrlEncoded.encodeString should skip more characters
- + 1036 Allow easy configuration of Scheduler-Threads and name them more
-   appropriate
- + 1485 Add systemd service file
- + 1743 Refactor jetty maven plugin goals to be more orthogonal
- + 2266 Jetty maven plugin reload is triggered each time the
-   `scanIntervalSeconds` pass
- + 2340 Remove raw ServletHandler usage examples from documentation
- + 2429 Review HttpClient backpressure semantic
- + 2578 Use addEventListener(EventListener listener)
- + 2709 current default for headerCacheSize is not large enough for many
-   requests
- + 2815 hpack fields are opaque octets
- + 3040 Allow RFC6265 Cookies to include optional SameSite attribute
- + 3083 The ini-template for jetty.console-capture.dir does not match the
-   default value
- + 3106 Websocket connection stats and request stats
- + 3558 Error notifications can be received after a successful websocket close
- + 3601 HTTP2 stall on reset streams
- + 3705 Review ClientUpgradeRequest exception handling
- + 3734 websocket suspend when input closed
- + 3747 Make Jetty Demo work with JPMS
- + 3787 Jetty client sometimes returns EOFException instead of
-   SSLHandshakeException on certificate errors.
- + 3804 Weld/CDI XML backwards compat?
- + 3806 Error Page handling Async race with ProxyServlet
- + 3822 trustAll will not work on some servers
- + 3829 Avoid sending empty trailer frames for http/2 responses
- + 3840 Byte-range request performance problems with large files
- + 3856 Different behaviour with maxFormContentSize=0 if Content-Length header
-   is present/missing
- + 3863 Enforce use of SNI
- + 3869 Update to ASM 7.2 for jdk 13
- + 3872 Review exposure of JavaxWebSocketServletContainerInitializer
- + 3876 WebSocketPartialListener is only called for initial frames, not for
-   continuation frames
- + 3884 @WebSocket without @OnWebSocketMessage handler fails when receiving a
-   continuation frame
- + 3888 BufferUtil.toBuffer(Resource resource,boolean direct) does not like
-   large (4G+) Resources
- + 3906 Fix for #3840 breaks Path encapsulation in PathResource
- + 3913 Clustered HttpSession IllegalStateException: Invalid for read
- + 3929 Deadlock between new HTTP2Connection() and Server.stop()
- + 3936 Race condition when modifying session + sendRedirect()
- + 3940 Double initialization of Log
- + 3951 Consider adding demand API to HTTP/2
- + 3952 Server configuration for direct/heap ByteBuffers
- + 3956 Remove and warn on use of illegal HTTP/2 response headers
- + 3957 CustomRequestLog bad usage of MethodHandles.lookup()
- + 3960 Fix HttpConfiguration copy constructor
- + 3964 Improve efficiency of listeners
- + 3968 WebSocket sporadic ReadPendingException using suspend/resume
- + 3969 X-Forwarded-Port header customization isn't possible
- + 3978 HTTP/2 fixes for robustly handling abnormal traffic and resource
-   exhaustion
- + 3983 JarFileResource incorrectly lists the contents of directories with
-   spaces
- + 3985 Improve lenient Cookie parsing
- + 3989 Inform custom ManagedSelector of dead selector via optional
-   onFailedSelect()
- + 4000 Add SameFileAliasChecker to help with FileSystem static file access
-   normalization on Mac and Windows
- + 4003 Quickstart broken in jetty-10
- + 4007 Getting NullPointerException while trying to run jetty start.run on
-   Windows
- + 4009 ServletContextHandler setSecurityHandler broke handler chain
- + 4020 Revert WebSocket ExtensionFactory change to interface
- + 4022 Servlet which is added by ServletRegistration can't be started
- + 4025 Provide more write-through behaviours for DefaultSessionCache
- + 4027 Ensure AbstractSessionDataStore cannot be used unless it is started
- + 4033 Ignore bad percent encodings in paths during
-   URIUtil.equalsIgnoreEncodings()
- + 4047 Gracefully stopped Jetty not flushing all response data
- + 4048 Multiple values in X-Forwarded-Port throw NumberFormatException
- + 4057 NullPointerException in o.e.j.h.HttpFields
- + 4058 Review Locker
- + 4064 java.lang.NullPointerException initializing embedded servlet
- + 4075 Do not fail on servlet-mapping with url-pattern /On*
- + 4076 Restarting quickstarted webapp throws IllegalStateException:
-   ServletContainerInitializersStarter already exists
- + 4082 Debug logging causes NullPointerException in client
- + 4084 Use of HttpConfiguration.setBlockingTimeout(long) in jetty.xml produces
-   warning on jetty-home startup
- + 4096 Thread in ReservedThreadExecutor does not exit when stopped
- + 4104 Frames are sent through ExtensionStack even if WebSocket Session is
-   closed
- + 4105 QueuedThreadPool increased thread usage and no idle thread decay
- + 4113 HttpClient fails with JDK 13 and TLS 1.3
- + 4115 Drop HTTP/2 pseudo headers
- + 4121 QueuedThreadPool should support ThreadFactory behaviors
- + 4122 QueuedThreadPool should reset thread interrupted on failed run
- + 4124 Run websocket autobahn tests with jetty and javax apis instead of just
-   with core.
- + 4128 OpenIdCredentials can't decode JWT ID token
- + 4132 Should be possible to use OIDC without metadata
- + 4138 OpenID module should use HttpClient instead of HttpURLConnection
- + 4141 ClassCastException with non-async Servlet + async Filter +
-   HttpServletRequestWrapper
- + 4142 Configurable HTTP/2 RateControl
- + 4144 Naked cast to Request should be avoided
- + 4150 Module org.eclipse.jetty.alpn.client not found, required by
-   org.eclipse.jetty.proxy
- + 4152 WebSocket autoFragment does not fragment based on maxFrameSize
- + 4156 IllegalStateException when forwarding to jsp with new session
- + 4161 Regression: EofException: request lifecycle violation
- + 4170 Client-side alias selection based on SSLEngine
- + 4173 NullPointerException warning in log from WebInfConfiguration after
-   upgrade
- + 4174 ConcurrentModificationException when stopping jetty:run-war
- + 4176 Should not set header if sendError has been called
- + 4177 Configure HTTP proxy with SslContextFactory
- + 4179 Improve HttpChannel$SendCallback references for GC
- + 4183 Jetty considers bootstrap injected class to be a "server class"
- + 4188 Spin in HttpOutput.close
- + 4190 Jetty hangs after thread blocked in SharedBlockingCallback.block()
-   called by HttpOutput.close
- + 4191 Increase GzipHandler minGzipSize default value
- + 4193 InetAccessHandler - new includeConnectors/excludeConnectors not quite
-   correct anymore
- + 4201 Throw SSLHandshakeException in case of TLS handshake failures
- + 4203 Some Transfer-Encoding and Content-Length combinations do not result in
-   expected 400 Bad Request
- + 4204 Transfer-Encoding behavior does not follow RFC7230
- + 4208 304 response with Content-Length fails, not conform to RFC7230
- + 4209 Unused TLS connection is not closed in Java 11
- + 4217 SslConnection.DecryptedEnpoint.flush eternal busy loop
- + 4222 Major/Minor Version wrong (jetty 10 is servlet 4)
- + 4227 First authorization request produced by OIDC module fails due to
-   inclusion of sessionid
- + 4236 clean up redirect code calculation for OpenIdAuthenticator
- + 4237 simplify openid module configuration
- + 4240 CGI form post results in 500 response if no character encoding
- + 4243 ErrorHandler produces invalid json error response
- + 4247 Cookie security attributes are going to mandated by Google Chrome
- + 4248 Websocket client UpgradeListener never reports success
- + 4251 Http 2.0 clients cannot upgrade protocol
- + 4258 RateControl should be per-connection
- + 4264 Spring Boot BasicErrorController no longer invoked
- + 4265 HttpChannel SEND_ERROR should use ErrorHandler.doError()
- + 4277 Reading streamed gzipped body never terminates
- + 4279 Regression: ResponseWriter#close blocks indefinitely
- + 4282 Review HttpParser handling in case of no content
- + 4283 Wrong package for OpenJDK8ClientALPNProcessor
- + 4284 Possible NullPointerException in Main.java when stopped from command
-   line
- + 4287 Move getUriLastPathSegment(URI uri) to URIUtil
- + 4296 Unable to create WebSocket connect if the query string of the URL has %
-   symbol.
- + 4301 Demand beforeContent is not forwarded
- + 4305 Jetty server ALPN shall alert fatal no_application_protocol if no
-   client application protocol is supported
- + 4325 Deprecate SniX509ExtendedKeyManager constructor without
-   SslContextFactory$Server
- + 4334 Better test ErrorHandler changes
- + 4342 OpenID module cannot create HttpClient in Jetty 10
-
-jetty-10.0.0-alpha0 - 11 July 2019
- + 113 Add support for NCSA Extended Log File Format
- + 114 Bring back overlay deployer
- + 132 ClientConnector abstraction
- + 207 Support javax.websocket version 1.1
- + 215 Add Conscrypt for native ALPN/TLS/SSL
- + 300 Implement Deflater / Inflater Object Pool
- + 482 jetty-osgi] The CCL while parsing the xml files should be set to a
-   combination of Jetty and Bundle-Classloader
- + 592 Support no-value Host header in HttpParser
- + 632 JMX tests rely on fixed port
- + 675 Slf4jLog.ignore() should produce at DEBUG level
- + 676 JavaUtilLog.ignore() should produce at DEBUG level
- + 677 Logging of .ignore() should indicate that it was an "Ignored Exception"
- + 746 Implement Servlet 4.0 Request.getMappings
- + 801 Jetty respond with status 200 instead of 304 while using Servlet 4.0
-   PushBuilder
- + 809 NPE in WebInfConfiguration for webapp deploy in osgi
- + 987 Can GzipHandler check if .gz file exists only by some paths?
- + 1135 Avoid allocations from Method.getParameterTypes() if possible
- + 1200 Use PathWatcher in DeploymentManager
- + 1350 Dynamic selection of the transport to use based on ALPN on the client
-   side
- + 1368 Need to support KeyStore/TrustStore with null passwords
- + 1384 Expose StatisticsServlet to webapp
- + 1468 Configure PKIX Revocation Checker for SslContextFactory
- + 1485 Add systemd service file
- + 1498 Add JRTResource to support future Java 9 classloader behaviors
- + 1499 ClasspathPattern needs MODULE ruleset to support future Java 9
-   classloader behaviors
- + 1503 IPv6 address needs normalization (without brackets) in
-   ForwardedRequestCustomizer
- + 1551 Move CookieCutter to jetty-http
- + 1571 Support Hazelcast session management in 9.4
- + 1574 TypeUtilTest#testGetLocationOfClass is user settings dependant
- + 1591 JDBCSessionDataStore doesn't work with root context on Oracle DB
- + 1592 CompressedContentFormat.tagEquals() - incorrect comparison of entity
-   tag hashes
- + 1595 HTTP/2: Avoid sending unnecessary stream WINDOW_UPDATE frames
- + 1599 WebSocketCloseTest fails
- + 1600 Update jndi.mod and plus.mod
- + 1603 WebSocketServerFactory NPE in toString()
- + 1604 WebSocketContainer stop needs improvement
- + 1605 ContainerProvider.getWebSocketContainer() behavior is not to spec
- + 1615 Password defaults in jetty-ssl-context.xml should be removed
- + 1618 AsyncContext.dispatch() does not use raw/encoded URI
- + 1622 HeaderFilter doesn't work if the response has been committed
- + 1623 JettyRunMojo use dependencies from reactor (outputdirectory)
- + 1625 Support new IANA declared Websocket Close Status Codes
- + 1637 Thread per connection retained in HTTP/2
- + 1638 Add it test for Maven Plugin
- + 1642 Using RewriteHandler with AsyncContext.dispatch() and
-   HttpServletRequestWrapper not possible
- + 1643 ProxyServlet always uses default number of selector threads -
-   constructor should allow to overwrite the default.
- + 1645 NotSerializableException: DoSFilter when using Non-Clustered Session
-   Management: File System
- + 1656 Improve configurability of ConnectionPools
- + 1671 Asymmetric usage of trailers in MetaData.Request
- + 1675 Session id should not be logged with INFO level in AbstractSessionCache
- + 1676 Remove Deprecated classes & methods
- + 1679 DeploymentManagerMBean not usable through JMX
- + 1682 Jetty-WarFragmentFolderPath directive has no effect in eclipse runtime
-   mode except for the first launch
- + 1692 Annotation scanning should ignore `module-info.class` files
- + 1698 Missing WWW-Authenticate from SpnegoAuthenticator when other
-   Authorization header provided
- + 1746 Remove LICENSE-CONTRIBUTOR?
- + 1836 Migrate Locker implementation to JVM ReentrantLock implementation
- + 1838 Servlet 4.0.0 artifact now available on central.maven.org
- + 1852 Fix quickstart generation for servlet 4.0
- + 1898 Request.getCookie() should ignore invalid cookies
- + 1956 Store and report build information of Jetty
- + 1977 jetty-http-spi tests fail with java9
- + 2061 WebSocket hangs in blockingWrite
- + 2075 Deprecating MultiException
- + 2095 Remove FastCGI multiplexing
- + 2103 Server should open connectors early in start sequence
- + 2108 Update licence headers and plugin for 2018
- + 2140 Infinispan and hazelcast changes to scavenge zombie expired sessions
- + 2172 Support javax.websocket 1.1
- + 2175 Refactor WebSocket close handling
- + 2191 JPMS Support
- + 2431 Upgrade to Junit 5
- + 2868 Adding SPNEGO authentication support for Jetty Client
- + 2901 Introduce HttpConnectionUpgrader as a conversation component in
-   HttpClient
- + 2909 Remove B64Code
- + 2948 Require JDK 11 for Jetty 10.x
- + 2978 Add module-info.java to relevant Jetty modules
- + 2983 Jetty 10 Configuration abstraction
- + 2985 Jetty 10 Configuration replacement algorithm incorrect
- + 2996 ContextHandler.setDefaultContextPath() not implemented for quickstart
- + 3009 Update Jetty 10 to use non-LEGACY Compliance Modes
- + 3010 Move old MultiPart parsing implementation to jetty-http
- + 3011 Move HttpCompliance to HttpConfiguration
- + 3012 Refactor HttpCompliance and HttpComplianceSection to be friendlier to
-   customization
- + 3129 javax-websocket-common pom.xml is wrong
- + 3139 NPE on
-   WebSocketServerContainerInitializer.configureContext(ServletContextHandler)
- + 3154 Add support for javax.net.ssl.HostnameVerifier to HttpClient
- + 3159 WebSocket permessage-deflate RSV1 validity check
- + 3162 Use Jetty specific Servlet API jar
- + 3165 Review javax-websocket-server tests
- + 3166 Run of autobahn websocket tests on CI
- + 3167 JavaxWebSocketServerContainerInitializer always creates a HttpClient
- + 3170 WebSocket proxy PoC
- + 3182 Restore websocket example files
- + 3186 Jetty maven plugin - javax.annotation.jar picked up from jetty plugin
-   rather than from applications classpath
- + 3197 Use jetty specific websocket API jar
- + 3213 MetaInfConfigurationTest tests disabled in jetty-10.0.x
- + 3216 Autobahn WebSocketServer failures in jetty 10
- + 3225 Response.sendError should not set reason
- + 3246 javax-websocket-tests exception stacktraces
- + 3249 Update to apache jasper 9.0.14 for jetty-10
- + 3274 OSGi versions of java.base classes in
-   org.apache.felix:org.osgi.foundation:jar conflicts with new rules on Java 9+
- + 3279 WebSocket write may hang forever
- + 3288 Correct websocket artifactIds on jetty-10.0.x
- + 3290 async websocket onOpen, onError and onClose in 10.0.x
- + 3298 Review jetty-10 websocket CompletableFuture usage
- + 3303 Update to jakarta ee javax artifacts for jetty-10
- + 3308 Remove deprecated methods from sessions
- + 3320 Review Jetty 10 module-info.java
- + 3333 Jetty 10 standalone cannot start on the module-path
- + 3340 Update PushCacheFilter to use Servlet 4.0 APIs
- + 3341 XmlBasedHttpClientProvider in Jetty 10
- + 3351 Restructure jetty-unixsocket module
- + 3374 JSR356 RemoteEndpoint.Async.setSendTimeout() logic invalid in Jetty
-   10.0.x
- + 3379 Tracking of WebSocket Sessions in WebSocket containers
- + 3380 WebSocket should support jetty-io Connection.Listener
- + 3382 Jetty WebSocket Session.suspend() not implemented
- + 3399 XmlConfiguration jetty.webapps.uri is the uri of the webapp not the
-   parent dir
- + 3406 restore and fix jetty websocket tests in jetty 10
- + 3412 problems with jetty 10 WebSocket session customizer
- + 3446 allow jetty WebSockets to be upgraded using WebSocketUpgradeFilter in
-   jetty-10
- + 3453 Removing moved Extension classes from jetty-websocket-api
- + 3458 ensure users of the jetty-websocket-api do not have to see
-   websocket-core classes
- + 3462 client validation of websocket upgrade response
- + 3465 websocket negotiation of extension configuration parameters
- + 3479 review and cleanup of jetty-websocket-api in jetty-10
- + 3484 ClassCastException when using websocket-core classes in
-   websocket-servlet
- + 3494 flaky tests in jetty-websocket-tests ClientCloseTest
- + 3564 Update jetty-10.0.x to apache jsp 9.0.19
- + 3608 Reply with 400 Bad request to malformed WebSocket handshake
- + 3616 Backport WebSocket SessionTracker from Jetty 10
- + 3648 javax.websocket client container incorrectly creates Server
-   SslContextFactory
- + 3661 JettyWebSocketServerContainer exposes websocket common classes
- + 3666 WebSocket - Handling sent 1009 close frame
- + 3696 Unwrap JavaxWebSocketClientContainer.connectToServer() exceptions
- + 3698 Missing WebSocket ServerContainer after server restart
- + 3700 stackoverflow in WebAppClassLoaderUrlStreamTest
- + 3705 Review ClientUpgradeRequest exception handling
- + 3708 Swap various java.lang.String replace() methods for better performant
-   ones
- + 3712 change maxIdleTime to idleTimeout in jetty-10 websockets
- + 3719 Clean up jetty-10 modules
- + 3726 Remove OSGi export uses of servlet-api from jetty-util
- + 3731 Add testing of CDI behaviors
- + 3736 NPE from WebAppClassLoader during CDI
- + 3746 ClassCastException in WriteFlusher.java - IdleState cannot be cast to
-   FailedState
- + 3749 Memory leak while processing AsyncListener annotations
- + 3751 Modern Configure DTD / FPI is used inconsistently
- + 3755 ServerWithAnnotations doesn't do anything
- + 3758 Avoid sending empty trailer frames for http/2 requests
- + 3762 WebSocketConnectionStatsTest test uses port 8080
- + 3782 X-Forwarded-Port overrides X-Forwarded-For
- + 3786 ALPN support for Java 14
- + 3789 XmlConfiguration set from property
- + 3798 ClasspathPattern match method throws NPE. URI can be null
- + 3799 Programmatically added listeners from
-   ServletContextListener.contextInitialzed() are not called
- + 3804 Weld/CDI XML backwards compat?
- + 3805 XmlConfiguration odd behavior for numbers
- + 3809 sending WebSocket close frame with error StatusCode does not do a hard
-   close (Jetty-10)
- + 3815 PropertyFileLoginModule adds user principle as a role
- + 3835 WebSocketSession are not being stopped properly
- + 3839 JavaxWebSocketServletContainerInitializer fails
- + 3840 Byte-range request performance problems with large files
- + 3849 ClosedChannelException from jetty-test-webapp javax websocket chat
-   example
-
 jetty-9.4.28.v20200408 - 08 April 2020
  + 847 Setting async timeout on WebSocketClient does not seem to timeout writes
  + 2896 Wrong Certificate Selected When Using Multiple Virtual Host Names in

build-resources/pom.xml

@@ -67,6 +67,7 @@
         <artifactId>maven-deploy-plugin</artifactId>
         <version>2.8.2</version>
         <configuration>
+          <!-- never deploy to a repository, only use in reactor -->
           <skip>true</skip>
         </configuration>
       </plugin>

jetty-client/src/main/java/org/eclipse/jetty/client/AbstractConnectionPool.java

@@ -18,74 +18,121 @@
 
 package org.eclipse.jetty.client;
 
+import java.io.IOException;
+import java.util.ArrayDeque;
 import java.util.Collection;
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.Queue;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
 
 import org.eclipse.jetty.client.api.Connection;
-import org.eclipse.jetty.util.AtomicBiInteger;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.Pool;
 import org.eclipse.jetty.util.Promise;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
 import org.eclipse.jetty.util.annotation.ManagedObject;
 import org.eclipse.jetty.util.component.Dumpable;
+import org.eclipse.jetty.util.thread.Sweeper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static java.util.stream.Collectors.toCollection;
+
 @ManagedObject
-public abstract class AbstractConnectionPool implements ConnectionPool, Dumpable
+public abstract class AbstractConnectionPool implements ConnectionPool, Dumpable, Sweeper.Sweepable
 {
     private static final Logger LOG = LoggerFactory.getLogger(AbstractConnectionPool.class);
 
-    /**
-     * The connectionCount encodes both the total connections plus the pending connection counts, so both can be atomically changed.
-     * The bottom 32 bits represent the total connections and the top 32 bits represent the pending connections.
-     */
-    private final AtomicBiInteger connections = new AtomicBiInteger();
-    private final AtomicBoolean closed = new AtomicBoolean();
     private final HttpDestination destination;
-    private final int maxConnections;
     private final Callback requester;
+    private final Pool<Connection> pool;
 
-    protected AbstractConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
+    protected AbstractConnectionPool(HttpDestination destination, int maxConnections, boolean cache, Callback requester)
     {
         this.destination = destination;
-        this.maxConnections = maxConnections;
         this.requester = requester;
+        @SuppressWarnings("unchecked")
+        Pool<Connection> pool = destination.getBean(Pool.class);
+        if (pool == null)
+        {
+            pool = new Pool<>(maxConnections, cache ? 1 : 0);
+            destination.addBean(pool);
+        }
+        this.pool = pool;
     }
 
-    protected HttpDestination getHttpDestination()
+    @Override
+    public CompletableFuture<Void> preCreateConnections(int connectionCount)
     {
-        return destination;
+        CompletableFuture<?>[] futures = new CompletableFuture[connectionCount];
+        for (int i = 0; i < connectionCount; i++)
+        {
+            futures[i] = tryCreateReturningFuture(pool.getMaxEntries());
+        }
+        return CompletableFuture.allOf(futures);
+    }
+
+    protected int getMaxMultiplex()
+    {
+        return pool.getMaxMultiplex();
+    }
+
+    protected void setMaxMultiplex(int maxMultiplex)
+    {
+        pool.setMaxMultiplex(maxMultiplex);
+    }
+
+    protected int getMaxUsageCount()
+    {
+        return pool.getMaxUsageCount();
+    }
+
+    protected void setMaxUsageCount(int maxUsageCount)
+    {
+        pool.setMaxUsageCount(maxUsageCount);
+    }
+
+    @ManagedAttribute(value = "The number of active connections", readonly = true)
+    public int getActiveConnectionCount()
+    {
+        return pool.getInUseConnectionCount();
+    }
+
+    @ManagedAttribute(value = "The number of idle connections", readonly = true)
+    public int getIdleConnectionCount()
+    {
+        return pool.getIdleConnectionCount();
     }
 
     @ManagedAttribute(value = "The max number of connections", readonly = true)
     public int getMaxConnectionCount()
     {
-        return maxConnections;
+        return pool.getMaxEntries();
     }
 
     @ManagedAttribute(value = "The number of connections", readonly = true)
     public int getConnectionCount()
     {
-        return connections.getLo();
+        return pool.size();
     }
 
     @ManagedAttribute(value = "The number of pending connections", readonly = true)
     public int getPendingConnectionCount()
     {
-        return connections.getHi();
+        return pool.getPendingConnectionCount();
     }
 
     @Override
     public boolean isEmpty()
     {
-        return connections.getLo() == 0;
+        return pool.size() == 0;
     }
 
     @Override
     public boolean isClosed()
     {
-        return closed.get();
+        return pool.isClosed();
     }
 
     @Override
@@ -112,101 +159,175 @@ public abstract class AbstractConnectionPool implements ConnectionPool, Dumpable
      */
     protected void tryCreate(int maxPending)
     {
-        while (true)
+        tryCreateReturningFuture(maxPending);
+    }
+
+    private CompletableFuture<Void> tryCreateReturningFuture(int maxPending)
+    {
+        CompletableFuture<Void> future = new CompletableFuture<>();
+
+        if (LOG.isDebugEnabled())
+            LOG.debug("tryCreate {}/{} connections {}/{} pending", pool.size(), pool.getMaxEntries(), getPendingConnectionCount(), maxPending);
+
+        Pool<Connection>.Entry entry = pool.reserve(maxPending);
+        if (entry == null)
         {
-            long encoded = connections.get();
-            int pending = AtomicBiInteger.getHi(encoded);
-            int total = AtomicBiInteger.getLo(encoded);
+            future.complete(null);
+            return future;
+        }
 
-            if (LOG.isDebugEnabled())
-                LOG.debug("tryCreate {}/{} connections {}/{} pending", total, maxConnections, pending, maxPending);
+        if (LOG.isDebugEnabled())
+            LOG.debug("newConnection {}/{} connections {}/{} pending", pool.size(), pool.getMaxEntries(), getPendingConnectionCount(), maxPending);
 
-            if (total >= maxConnections)
-                return;
-
-            if (maxPending >= 0 && pending >= maxPending)
-                return;
-
-            if (connections.compareAndSet(encoded, pending + 1, total + 1))
+        destination.newConnection(new Promise<>()
+        {
+            @Override
+            public void succeeded(Connection connection)
             {
                 if (LOG.isDebugEnabled())
-                    LOG.debug("newConnection {}/{} connections {}/{} pending", total + 1, maxConnections, pending + 1, maxPending);
-
-                destination.newConnection(new Promise<>()
-                {
-                    @Override
-                    public void succeeded(Connection connection)
-                    {
-                        if (LOG.isDebugEnabled())
-                            LOG.debug("Connection {}/{} creation succeeded {}", total + 1, maxConnections, connection);
-                        connections.add(-1, 0);
-                        onCreated(connection);
-                        proceed();
-                    }
-
-                    @Override
-                    public void failed(Throwable x)
-                    {
-                        if (LOG.isDebugEnabled())
-                            LOG.debug("Connection " + (total + 1) + "/" + maxConnections + " creation failed", x);
-                        connections.add(-1, -1);
-                        requester.failed(x);
-                    }
-                });
-
-                return;
+                    LOG.debug("Connection {}/{} creation succeeded {}", pool.size(), pool.getMaxEntries(), connection);
+                adopt(entry, connection);
+                future.complete(null);
+                proceed();
             }
-        }
+
+            @Override
+            public void failed(Throwable x)
+            {
+                if (LOG.isDebugEnabled())
+                    LOG.debug("Connection " + pool.size() + "/" + pool.getMaxEntries() + " creation failed", x);
+                pool.remove(entry);
+                future.completeExceptionally(x);
+                requester.failed(x);
+            }
+        });
+        return future;
     }
 
     @Override
     public boolean accept(Connection connection)
     {
-        while (true)
-        {
-            int count = connections.getLo();
-            if (count >= maxConnections)
-                return false;
-            if (connections.compareAndSetLo(count, count + 1))
-                return true;
-        }
+        Pool<Connection>.Entry entry = pool.reserve(-1);
+        if (entry == null)
+            return false;
+        adopt(entry, connection);
+        return true;
     }
 
-    protected abstract void onCreated(Connection connection);
-
     protected void proceed()
     {
         requester.succeeded();
     }
 
-    protected abstract Connection activate();
-
-    protected Connection active(Connection connection)
+    private void adopt(Pool<Connection>.Entry entry, Connection connection)
     {
+        if (!(connection instanceof Attachable))
+            throw new IllegalArgumentException("Invalid connection object: " + connection);
+        Attachable attachable = (Attachable)connection;
+        attachable.setAttachment(entry);
         if (LOG.isDebugEnabled())
-            LOG.debug("Connection active {}", connection);
-        acquired(connection);
-        return connection;
+            LOG.debug("onCreating {}", entry);
+        onCreated(connection);
+        entry.enable(connection);
+        idle(connection, false);
     }
 
-    protected void acquired(Connection connection)
+    protected Connection activate()
+    {
+        Pool<Connection>.Entry entry = pool.acquire();
+        if (LOG.isDebugEnabled())
+            LOG.debug("activated '{}'", entry);
+        if (entry != null)
+        {
+            Connection connection = entry.getPooled();
+            acquired(connection);
+            return connection;
+        }
+        return null;
+    }
+
+    @Override
+    public boolean isActive(Connection connection)
+    {
+        if (!(connection instanceof Attachable))
+            throw new IllegalArgumentException("Invalid connection object: " + connection);
+        Attachable attachable = (Attachable)connection;
+        @SuppressWarnings("unchecked")
+        Pool<Connection>.Entry entry = (Pool<Connection>.Entry)attachable.getAttachment();
+        if (entry == null)
+            return false;
+        if (LOG.isDebugEnabled())
+            LOG.debug("isActive {}", entry);
+        return !entry.isIdle();
+    }
+
+    @Override
+    public boolean release(Connection connection)
+    {
+        if (!deactivate(connection))
+            return false;
+        released(connection);
+        return idle(connection, isClosed());
+    }
+
+    protected boolean deactivate(Connection connection)
+    {
+        if (!(connection instanceof Attachable))
+            throw new IllegalArgumentException("Invalid connection object: " + connection);
+        Attachable attachable = (Attachable)connection;
+        @SuppressWarnings("unchecked")
+        Pool<Connection>.Entry entry = (Pool<Connection>.Entry)attachable.getAttachment();
+        if (entry == null)
+            return true;
+        if (LOG.isDebugEnabled())
+            LOG.debug("releasing {}", entry);
+        boolean reusable = pool.release(entry);
+        if (!reusable)
+        {
+            remove(connection);
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public boolean remove(Connection connection)
+    {
+        return remove(connection, false);
+    }
+
+    protected boolean remove(Connection connection, boolean force)
+    {
+        if (!(connection instanceof Attachable))
+            throw new IllegalArgumentException("Invalid connection object: " + connection);
+        Attachable attachable = (Attachable)connection;
+        @SuppressWarnings("unchecked")
+        Pool<Connection>.Entry entry = (Pool<Connection>.Entry)attachable.getAttachment();
+        if (entry == null)
+            return false;
+        attachable.setAttachment(null);
+        if (LOG.isDebugEnabled())
+            LOG.debug("removing {}", entry);
+        boolean removed = pool.remove(entry);
+        if (removed || force)
+        {
+            released(connection);
+            removed(connection);
+        }
+        return removed;
+    }
+
+    protected void onCreated(Connection connection)
     {
     }
 
     protected boolean idle(Connection connection, boolean close)
     {
-        if (close)
-        {
-            if (LOG.isDebugEnabled())
-                LOG.debug("Connection idle close {}", connection);
-            return false;
-        }
-        else
-        {
-            if (LOG.isDebugEnabled())
-                LOG.debug("Connection idle {}", connection);
-            return true;
-        }
+        return !close;
+    }
+
+    protected void acquired(Connection connection)
+    {
     }
 
     protected void released(Connection connection)
@@ -215,28 +336,68 @@ public abstract class AbstractConnectionPool implements ConnectionPool, Dumpable
 
     protected void removed(Connection connection)
     {
-        int pooled = connections.addAndGetLo(-1);
-        if (LOG.isDebugEnabled())
-            LOG.debug("Connection removed {} - pooled: {}", connection, pooled);
+    }
+
+    Queue<Connection> getIdleConnections()
+    {
+        return pool.values().stream()
+            .filter(Pool.Entry::isIdle)
+            .filter(entry -> !entry.isClosed())
+            .map(Pool.Entry::getPooled)
+            .collect(toCollection(ArrayDeque::new));
+    }
+
+    Collection<Connection> getActiveConnections()
+    {
+        return pool.values().stream()
+            .filter(entry -> !entry.isIdle())
+            .filter(entry -> !entry.isClosed())
+            .map(Pool.Entry::getPooled)
+            .collect(Collectors.toList());
     }
 
     @Override
     public void close()
     {
-        if (closed.compareAndSet(false, true))
-        {
-            connections.set(0, 0);
-        }
-    }
-
-    protected void close(Collection<Connection> connections)
-    {
-        connections.forEach(Connection::close);
+        pool.close();
     }
 
     @Override
-    public String dump()
+    public void dump(Appendable out, String indent) throws IOException
     {
-        return Dumpable.dump(this);
+        Dumpable.dumpObjects(out, indent, this);
+    }
+
+    @Override
+    public boolean sweep()
+    {
+        pool.values().stream().filter(entry -> entry.getPooled() instanceof Sweeper.Sweepable).forEach(entry ->
+        {
+            Connection connection = entry.getPooled();
+            if (((Sweeper.Sweepable)connection).sweep())
+            {
+                boolean removed = remove(connection);
+                LOG.warn("Connection swept: {}{}{} from active connections{}{}",
+                    connection,
+                    System.lineSeparator(),
+                    removed ? "Removed" : "Not removed",
+                    System.lineSeparator(),
+                    dump());
+            }
+        });
+        return false;
+    }
+
+    @Override
+    public String toString()
+    {
+        return String.format("%s@%x[c=%d/%d/%d,a=%d,i=%d]",
+            getClass().getSimpleName(),
+            hashCode(),
+            getPendingConnectionCount(),
+            getConnectionCount(),
+            getMaxConnectionCount(),
+            getActiveConnectionCount(),
+            getIdleConnectionCount());
     }
 }

jetty-client/src/main/java/org/eclipse/jetty/client/ConnectionPool.java

@@ -19,6 +19,7 @@
 package org.eclipse.jetty.client;
 
 import java.io.Closeable;
+import java.util.concurrent.CompletableFuture;
 
 import org.eclipse.jetty.client.api.Connection;
 
@@ -27,6 +28,16 @@ import org.eclipse.jetty.client.api.Connection;
  */
 public interface ConnectionPool extends Closeable
 {
+    /**
+     * Optionally pre-create up to <code>connectionCount</code>
+     * connections so they are immediately ready for use.
+     * @param connectionCount the number of connections to pre-start.
+     */
+    default CompletableFuture<Void> preCreateConnections(int connectionCount)
+    {
+        return CompletableFuture.completedFuture(null);
+    }
+
     /**
      * @param connection the connection to test
      * @return whether the given connection is currently in use

jetty-client/src/main/java/org/eclipse/jetty/client/DuplexConnectionPool.java

@@ -18,303 +18,33 @@
 
 package org.eclipse.jetty.client;
 
-import java.io.IOException;
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Deque;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Queue;
-import java.util.Set;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.stream.Collectors;
-
-import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
 import org.eclipse.jetty.util.annotation.ManagedObject;
-import org.eclipse.jetty.util.component.Dumpable;
-import org.eclipse.jetty.util.component.DumpableCollection;
-import org.eclipse.jetty.util.thread.Sweeper;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @ManagedObject
-public class DuplexConnectionPool extends AbstractConnectionPool implements Sweeper.Sweepable
+public class DuplexConnectionPool extends AbstractConnectionPool
 {
-    private static final Logger LOG = LoggerFactory.getLogger(DuplexConnectionPool.class);
-
-    private final ReentrantLock lock = new ReentrantLock();
-    private final Deque<Connection> idleConnections;
-    private final Set<Connection> activeConnections;
-
     public DuplexConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
     {
-        super(destination, maxConnections, requester);
-        this.idleConnections = new ArrayDeque<>(maxConnections);
-        this.activeConnections = new HashSet<>(maxConnections);
+        this(destination, maxConnections, true, requester);
     }
 
-    protected void lock()
+    public DuplexConnectionPool(HttpDestination destination, int maxConnections, boolean cache, Callback requester)
     {
-        lock.lock();
-    }
-
-    protected void unlock()
-    {
-        lock.unlock();
-    }
-
-    @ManagedAttribute(value = "The number of idle connections", readonly = true)
-    public int getIdleConnectionCount()
-    {
-        lock();
-        try
-        {
-            return idleConnections.size();
-        }
-        finally
-        {
-            unlock();
-        }
-    }
-
-    @ManagedAttribute(value = "The number of active connections", readonly = true)
-    public int getActiveConnectionCount()
-    {
-        lock();
-        try
-        {
-            return activeConnections.size();
-        }
-        finally
-        {
-            unlock();
-        }
-    }
-
-    public Queue<Connection> getIdleConnections()
-    {
-        return idleConnections;
-    }
-
-    public Collection<Connection> getActiveConnections()
-    {
-        return activeConnections;
+        super(destination, maxConnections, cache, requester);
     }
 
     @Override
-    public boolean isActive(Connection connection)
+    @ManagedAttribute(value = "The maximum amount of times a connection is used before it gets closed")
+    public int getMaxUsageCount()
     {
-        lock();
-        try
-        {
-            return activeConnections.contains(connection);
-        }
-        finally
-        {
-            unlock();
-        }
+        return super.getMaxUsageCount();
     }
 
     @Override
-    protected void onCreated(Connection connection)
+    public void setMaxUsageCount(int maxUsageCount)
     {
-        lock();
-        try
-        {
-            // Use "cold" new connections as last.
-            idleConnections.offer(connection);
-        }
-        finally
-        {
-            unlock();
-        }
-
-        idle(connection, false);
-    }
-
-    @Override
-    protected Connection activate()
-    {
-        Connection connection;
-        lock();
-        try
-        {
-            connection = idleConnections.poll();
-            if (connection == null)
-                return null;
-            activeConnections.add(connection);
-        }
-        finally
-        {
-            unlock();
-        }
-
-        return active(connection);
-    }
-
-    @Override
-    public boolean release(Connection connection)
-    {
-        boolean closed = isClosed();
-        lock();
-        try
-        {
-            if (!activeConnections.remove(connection))
-                return false;
-
-            if (!closed)
-            {
-                // Make sure we use "hot" connections first.
-                deactivate(connection);
-            }
-        }
-        finally
-        {
-            unlock();
-        }
-
-        released(connection);
-        return idle(connection, closed);
-    }
-
-    protected boolean deactivate(Connection connection)
-    {
-        return idleConnections.offerFirst(connection);
-    }
-
-    @Override
-    public boolean remove(Connection connection)
-    {
-        return remove(connection, false);
-    }
-
-    protected boolean remove(Connection connection, boolean force)
-    {
-        boolean activeRemoved;
-        boolean idleRemoved;
-        lock();
-        try
-        {
-            activeRemoved = activeConnections.remove(connection);
-            idleRemoved = idleConnections.remove(connection);
-        }
-        finally
-        {
-            unlock();
-        }
-
-        if (activeRemoved || force)
-            released(connection);
-        boolean removed = activeRemoved || idleRemoved || force;
-        if (removed)
-            removed(connection);
-        return removed;
-    }
-
-    @Override
-    public void close()
-    {
-        super.close();
-
-        List<Connection> connections = new ArrayList<>();
-        lock();
-        try
-        {
-            connections.addAll(idleConnections);
-            idleConnections.clear();
-            connections.addAll(activeConnections);
-            activeConnections.clear();
-        }
-        finally
-        {
-            unlock();
-        }
-
-        close(connections);
-    }
-
-    @Override
-    public void dump(Appendable out, String indent) throws IOException
-    {
-        DumpableCollection active;
-        DumpableCollection idle;
-        lock();
-        try
-        {
-            active = new DumpableCollection("active", new ArrayList<>(activeConnections));
-            idle = new DumpableCollection("idle", new ArrayList<>(idleConnections));
-        }
-        finally
-        {
-            unlock();
-        }
-        dump(out, indent, active, idle);
-    }
-
-    protected void dump(Appendable out, String indent, Object... items) throws IOException
-    {
-        Dumpable.dumpObjects(out, indent, this, items);
-    }
-
-    @Override
-    public boolean sweep()
-    {
-        List<Connection> toSweep;
-        lock();
-        try
-        {
-            toSweep = activeConnections.stream()
-                .filter(connection -> connection instanceof Sweeper.Sweepable)
-                .collect(Collectors.toList());
-        }
-        finally
-        {
-            unlock();
-        }
-
-        for (Connection connection : toSweep)
-        {
-            if (((Sweeper.Sweepable)connection).sweep())
-            {
-                boolean removed = remove(connection, true);
-                LOG.warn("Connection swept: {}{}{} from active connections{}{}",
-                    connection,
-                    System.lineSeparator(),
-                    removed ? "Removed" : "Not removed",
-                    System.lineSeparator(),
-                    dump());
-            }
-        }
-
-        return false;
-    }
-
-    @Override
-    public String toString()
-    {
-        int activeSize;
-        int idleSize;
-        lock();
-        try
-        {
-            activeSize = activeConnections.size();
-            idleSize = idleConnections.size();
-        }
-        finally
-        {
-            unlock();
-        }
-
-        return String.format("%s@%x[c=%d/%d/%d,a=%d,i=%d]",
-            getClass().getSimpleName(),
-            hashCode(),
-            getPendingConnectionCount(),
-            getConnectionCount(),
-            getMaxConnectionCount(),
-            activeSize,
-            idleSize);
+        super.setMaxUsageCount(maxUsageCount);
     }
 }

jetty-client/src/main/java/org/eclipse/jetty/client/HttpConnection.java

@@ -35,17 +35,19 @@ import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpVersion;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.HttpCookieStore;
 import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public abstract class HttpConnection implements IConnection
+public abstract class HttpConnection implements IConnection, Attachable
 {
     private static final Logger LOG = LoggerFactory.getLogger(HttpConnection.class);
 
     private final AutoLock lock = new AutoLock();
     private final HttpDestination destination;
+    private Object attachment;
     private int idleTimeoutGuard;
     private long idleTimeoutStamp;
 
@@ -273,6 +275,18 @@ public abstract class HttpConnection implements IConnection
         }
     }
 
+    @Override
+    public void setAttachment(Object obj)
+    {
+        this.attachment = obj;
+    }
+
+    @Override
+    public Object getAttachment()
+    {
+        return attachment;
+    }
+
     @Override
     public String toString()
     {

jetty-client/src/main/java/org/eclipse/jetty/client/HttpDestination.java

@@ -427,6 +427,7 @@ public abstract class HttpDestination extends ContainerLifeCycle implements Dest
         {
             if (connectionPool.isActive(connection))
             {
+                // trigger the next request after releasing the connection
                 if (connectionPool.release(connection))
                     send(false);
                 else

jetty-client/src/main/java/org/eclipse/jetty/client/HttpProxy.java

@@ -37,6 +37,7 @@ import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.io.ClientConnectionFactory;
 import org.eclipse.jetty.io.ClientConnector;
 import org.eclipse.jetty.io.EndPoint;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.Promise;
 import org.eclipse.jetty.util.ssl.SslContextFactory;
 import org.slf4j.Logger;
@@ -276,11 +277,12 @@ public class HttpProxy extends ProxyConfiguration.Proxy
         }
     }
 
-    private static class ProxyConnection implements Connection
+    private static class ProxyConnection implements Connection, Attachable
     {
         private final Destination destination;
         private final Connection connection;
         private final Promise<Connection> promise;
+        private Object attachment;
 
         private ProxyConnection(Destination destination, Connection connection, Promise<Connection> promise)
         {
@@ -313,6 +315,18 @@ public class HttpProxy extends ProxyConfiguration.Proxy
         {
             return connection.isClosed();
         }
+
+        @Override
+        public void setAttachment(Object obj)
+        {
+            this.attachment = obj;
+        }
+
+        @Override
+        public Object getAttachment()
+        {
+            return attachment;
+        }
     }
 
     private static class TunnelPromise implements Promise<Connection>

jetty-client/src/main/java/org/eclipse/jetty/client/LeakTrackingConnectionPool.java

@@ -39,7 +39,7 @@ public class LeakTrackingConnectionPool extends DuplexConnectionPool
 
     public LeakTrackingConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
     {
-        super(destination, maxConnections, requester);
+        super((HttpDestination)destination, maxConnections, requester);
         start();
     }
 

jetty-client/src/main/java/org/eclipse/jetty/client/MultiplexConnectionPool.java

@@ -18,309 +18,47 @@
 
 package org.eclipse.jetty.client;
 
-import java.io.IOException;
-import java.util.ArrayDeque;
-import java.util.ArrayList;
-import java.util.Deque;
-import java.util.Iterator;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
-
-import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.util.Callback;
-import org.eclipse.jetty.util.component.Dumpable;
-import org.eclipse.jetty.util.component.DumpableCollection;
-import org.eclipse.jetty.util.thread.AutoLock;
-import org.eclipse.jetty.util.thread.Sweeper;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.eclipse.jetty.util.annotation.ManagedAttribute;
+import org.eclipse.jetty.util.annotation.ManagedObject;
 
-public class MultiplexConnectionPool extends AbstractConnectionPool implements ConnectionPool.Multiplexable, Sweeper.Sweepable
+@ManagedObject
+public class MultiplexConnectionPool extends AbstractConnectionPool implements ConnectionPool.Multiplexable
 {
-    private static final Logger LOG = LoggerFactory.getLogger(MultiplexConnectionPool.class);
-
-    private final AutoLock lock = new AutoLock();
-    private final Deque<Holder> idleConnections;
-    private final Map<Connection, Holder> activeConnections;
-    private int maxMultiplex;
-
     public MultiplexConnectionPool(HttpDestination destination, int maxConnections, Callback requester, int maxMultiplex)
     {
-        super(destination, maxConnections, requester);
-        this.idleConnections = new ArrayDeque<>(maxConnections);
-        this.activeConnections = new LinkedHashMap<>(maxConnections);
-        this.maxMultiplex = maxMultiplex;
-    }
-
-    @Override
-    public Connection acquire(boolean create)
-    {
-        Connection connection = activate();
-        if (connection == null && create)
-        {
-            int queuedRequests = getHttpDestination().getQueuedRequestCount();
-            int maxMultiplex = getMaxMultiplex();
-            int maxPending = ceilDiv(queuedRequests, maxMultiplex);
-            tryCreate(maxPending);
-            connection = activate();
-        }
-        return connection;
-    }
-
-    /**
-     * @param a the dividend
-     * @param b the divisor
-     * @return the ceiling of the algebraic quotient
-     */
-    private static int ceilDiv(int a, int b)
-    {
-        return (a + b - 1) / b;
+        this(destination, maxConnections, true, requester, maxMultiplex);
+    }
+
+    public MultiplexConnectionPool(HttpDestination destination, int maxConnections, boolean cache, Callback requester, int maxMultiplex)
+    {
+        super(destination, maxConnections, cache, requester);
+        setMaxMultiplex(maxMultiplex);
     }
 
     @Override
+    @ManagedAttribute(value = "The multiplexing factor of connections")
     public int getMaxMultiplex()
     {
-        try (AutoLock l = lock.lock())
-        {
-            return maxMultiplex;
-        }
+        return super.getMaxMultiplex();
     }
 
     @Override
     public void setMaxMultiplex(int maxMultiplex)
     {
-        try (AutoLock l = lock.lock())
-        {
-            this.maxMultiplex = maxMultiplex;
-        }
+        super.setMaxMultiplex(maxMultiplex);
     }
 
     @Override
-    public boolean accept(Connection connection)
+    @ManagedAttribute(value = "The maximum amount of times a connection is used before it gets closed")
+    public int getMaxUsageCount()
     {
-        boolean accepted = super.accept(connection);
-        if (LOG.isDebugEnabled())
-            LOG.debug("Accepted {} {}", accepted, connection);
-        if (accepted)
-        {
-            try (AutoLock l = lock.lock())
-            {
-                Holder holder = new Holder(connection);
-                activeConnections.put(connection, holder);
-                ++holder.count;
-            }
-            active(connection);
-        }
-        return accepted;
+        return super.getMaxUsageCount();
     }
 
     @Override
-    public boolean isActive(Connection connection)
+    public void setMaxUsageCount(int maxUsageCount)
     {
-        try (AutoLock l = lock.lock())
-        {
-            return activeConnections.containsKey(connection);
-        }
-    }
-
-    @Override
-    protected void onCreated(Connection connection)
-    {
-        try (AutoLock l = lock.lock())
-        {
-            // Use "cold" connections as last.
-            idleConnections.offer(new Holder(connection));
-        }
-        idle(connection, false);
-    }
-
-    @Override
-    protected Connection activate()
-    {
-        Holder result = null;
-        try (AutoLock l = lock.lock())
-        {
-            for (Holder holder : activeConnections.values())
-            {
-                if (holder.count < maxMultiplex)
-                {
-                    result = holder;
-                    break;
-                }
-            }
-
-            if (result == null)
-            {
-                Holder holder = idleConnections.poll();
-                if (holder == null)
-                    return null;
-                activeConnections.put(holder.connection, holder);
-                result = holder;
-            }
-
-            ++result.count;
-        }
-        return active(result.connection);
-    }
-
-    @Override
-    public boolean release(Connection connection)
-    {
-        boolean closed = isClosed();
-        boolean idle = false;
-        Holder holder;
-        try (AutoLock l = lock.lock())
-        {
-            holder = activeConnections.get(connection);
-            if (holder != null)
-            {
-                int count = --holder.count;
-                if (count == 0)
-                {
-                    activeConnections.remove(connection);
-                    if (!closed)
-                    {
-                        idleConnections.offerFirst(holder);
-                        idle = true;
-                    }
-                }
-            }
-        }
-        if (holder == null)
-            return false;
-
-        released(connection);
-        if (idle || closed)
-            return idle(connection, closed);
-        return true;
-    }
-
-    @Override
-    public boolean remove(Connection connection)
-    {
-        return remove(connection, false);
-    }
-
-    protected boolean remove(Connection connection, boolean force)
-    {
-        boolean activeRemoved = true;
-        boolean idleRemoved = false;
-        try (AutoLock l = lock.lock())
-        {
-            Holder holder = activeConnections.remove(connection);
-            if (holder == null)
-            {
-                activeRemoved = false;
-                for (Iterator<Holder> iterator = idleConnections.iterator(); iterator.hasNext(); )
-                {
-                    holder = iterator.next();
-                    if (holder.connection == connection)
-                    {
-                        idleRemoved = true;
-                        iterator.remove();
-                        break;
-                    }
-                }
-            }
-        }
-        if (activeRemoved || force)
-            released(connection);
-        boolean removed = activeRemoved || idleRemoved || force;
-        if (removed)
-            removed(connection);
-        return removed;
-    }
-
-    @Override
-    public void close()
-    {
-        super.close();
-        List<Connection> connections;
-        try (AutoLock l = lock.lock())
-        {
-            connections = idleConnections.stream().map(holder -> holder.connection).collect(Collectors.toList());
-            connections.addAll(activeConnections.keySet());
-        }
-        close(connections);
-    }
-
-    @Override
-    public void dump(Appendable out, String indent) throws IOException
-    {
-        DumpableCollection active;
-        DumpableCollection idle;
-        try (AutoLock l = lock.lock())
-        {
-            active = new DumpableCollection("active", new ArrayList<>(activeConnections.values()));
-            idle = new DumpableCollection("idle", new ArrayList<>(idleConnections));
-        }
-        Dumpable.dumpObjects(out, indent, this, active, idle);
-    }
-
-    @Override
-    public boolean sweep()
-    {
-        List<Connection> toSweep = new ArrayList<>();
-        try (AutoLock l = lock.lock())
-        {
-            activeConnections.values().stream()
-                .map(holder -> holder.connection)
-                .filter(connection -> connection instanceof Sweeper.Sweepable)
-                .collect(Collectors.toCollection(() -> toSweep));
-        }
-        for (Connection connection : toSweep)
-        {
-            if (((Sweeper.Sweepable)connection).sweep())
-            {
-                boolean removed = remove(connection, true);
-                LOG.warn("Connection swept: {}{}{} from active connections{}{}",
-                    connection,
-                    System.lineSeparator(),
-                    removed ? "Removed" : "Not removed",
-                    System.lineSeparator(),
-                    dump());
-            }
-        }
-        return false;
-    }
-
-    @Override
-    public String toString()
-    {
-        int activeSize;
-        int idleSize;
-        try (AutoLock l = lock.lock())
-        {
-            activeSize = activeConnections.size();
-            idleSize = idleConnections.size();
-        }
-        return String.format("%s@%x[connections=%d/%d/%d,multiplex=%d,active=%d,idle=%d]",
-            getClass().getSimpleName(),
-            hashCode(),
-            getPendingConnectionCount(),
-            getConnectionCount(),
-            getMaxConnectionCount(),
-            getMaxMultiplex(),
-            activeSize,
-            idleSize);
-    }
-
-    private static class Holder
-    {
-        private final Connection connection;
-        private int count;
-
-        private Holder(Connection connection)
-        {
-            this.connection = connection;
-        }
-
-        @Override
-        public String toString()
-        {
-            return String.format("%s[%d]", connection, count);
-        }
+        super.setMaxUsageCount(maxUsageCount);
     }
 }

jetty-client/src/main/java/org/eclipse/jetty/client/RoundRobinConnectionPool.java

@@ -18,23 +18,22 @@
 
 package org.eclipse.jetty.client;
 
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.Pool;
 import org.eclipse.jetty.util.annotation.ManagedObject;
-import org.eclipse.jetty.util.component.Dumpable;
-import org.eclipse.jetty.util.thread.AutoLock;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @ManagedObject
-public class RoundRobinConnectionPool extends AbstractConnectionPool implements ConnectionPool.Multiplexable
+public class RoundRobinConnectionPool extends MultiplexConnectionPool
 {
-    private final AutoLock lock = new AutoLock();
-    private final List<Entry> entries;
-    private int maxMultiplex;
-    private int index;
+    private static final Logger LOG = LoggerFactory.getLogger(RoundRobinConnectionPool.class);
+
+    private final AtomicInteger offset = new AtomicInteger();
+    private final Pool<Connection> pool;
 
     public RoundRobinConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
     {
@@ -43,220 +42,31 @@ public class RoundRobinConnectionPool extends AbstractConnectionPool implements
 
     public RoundRobinConnectionPool(HttpDestination destination, int maxConnections, Callback requester, int maxMultiplex)
     {
-        super(destination, maxConnections, requester);
-        entries = new ArrayList<>(maxConnections);
-        for (int i = 0; i < maxConnections; ++i)
-        {
-            entries.add(new Entry());
-        }
-        this.maxMultiplex = maxMultiplex;
-    }
-
-    @Override
-    public int getMaxMultiplex()
-    {
-        try (AutoLock l = lock.lock())
-        {
-            return maxMultiplex;
-        }
-    }
-
-    @Override
-    public void setMaxMultiplex(int maxMultiplex)
-    {
-        try (AutoLock l = lock.lock())
-        {
-            this.maxMultiplex = maxMultiplex;
-        }
-    }
-
-    /**
-     * <p>Returns an idle connection, if available, following a round robin algorithm;
-     * otherwise it always tries to create a new connection, up until the max connection count.</p>
-     *
-     * @param create this parameter is ignored and assumed to be always {@code true}
-     * @return an idle connection or {@code null} if no idle connections are available
-     */
-    @Override
-    public Connection acquire(boolean create)
-    {
-        // The nature of this connection pool is such that a
-        // connection must always be present in the next slot.
-        return super.acquire(true);
-    }
-
-    @Override
-    protected void onCreated(Connection connection)
-    {
-        try (AutoLock l = lock.lock())
-        {
-            for (Entry entry : entries)
-            {
-                if (entry.connection == null)
-                {
-                    entry.connection = connection;
-                    break;
-                }
-            }
-        }
-        idle(connection, false);
+        super(destination, maxConnections, false, requester, maxMultiplex);
+        pool = destination.getBean(Pool.class);
     }
 
     @Override
     protected Connection activate()
     {
-        Connection connection = null;
-        try (AutoLock l = lock.lock())
-        {
-            int offset = 0;
-            int capacity = getMaxConnectionCount();
-            while (offset < capacity)
-            {
-                int idx = index + offset;
-                if (idx >= capacity)
-                    idx -= capacity;
-
-                Entry entry = entries.get(idx);
-
-                if (entry.connection == null)
-                    break;
-
-                if (entry.active < getMaxMultiplex())
-                {
-                    ++entry.active;
-                    ++entry.used;
-                    connection = entry.connection;
-                    index += offset + 1;
-                    if (index >= capacity)
-                        index -= capacity;
-                    break;
-                }
-
-                ++offset;
-            }
-        }
-        return connection == null ? null : active(connection);
+        int offset = this.offset.get();
+        Connection connection = activate(offset);
+        if (connection != null)
+            this.offset.getAndIncrement();
+        return connection;
     }
 
-    @Override
-    public boolean isActive(Connection connection)
+    private Connection activate(int offset)
     {
-        try (AutoLock l = lock.lock())
+        Pool<Connection>.Entry entry = pool.acquireAt(Math.abs(offset % pool.getMaxEntries()));
+        if (LOG.isDebugEnabled())
+            LOG.debug("activated '{}'", entry);
+        if (entry != null)
         {
-            for (Entry entry : entries)
-            {
-                if (entry.connection == connection)
-                    return entry.active > 0;
-            }
-            return false;
-        }
-    }
-
-    @Override
-    public boolean release(Connection connection)
-    {
-        boolean found = false;
-        boolean idle = false;
-        try (AutoLock l = lock.lock())
-        {
-            for (Entry entry : entries)
-            {
-                if (entry.connection == connection)
-                {
-                    found = true;
-                    int active = --entry.active;
-                    idle = active == 0;
-                    break;
-                }
-            }
-        }
-        if (!found)
-            return false;
-        released(connection);
-        if (idle)
-            return idle(connection, isClosed());
-        return true;
-    }
-
-    @Override
-    public boolean remove(Connection connection)
-    {
-        boolean found = false;
-        try (AutoLock l = lock.lock())
-        {
-            for (Entry entry : entries)
-            {
-                if (entry.connection == connection)
-                {
-                    found = true;
-                    entry.reset();
-                    break;
-                }
-            }
-        }
-        if (found)
-        {
-            released(connection);
-            removed(connection);
-        }
-        return found;
-    }
-
-    @Override
-    public void dump(Appendable out, String indent) throws IOException
-    {
-        List<Entry> connections;
-        try (AutoLock l = lock.lock())
-        {
-            connections = new ArrayList<>(entries);
-        }
-        Dumpable.dumpObjects(out, indent, out, connections);
-    }
-
-    @Override
-    public String toString()
-    {
-        int present = 0;
-        int active = 0;
-        try (AutoLock l = lock.lock())
-        {
-            for (Entry entry : entries)
-            {
-                if (entry.connection != null)
-                {
-                    ++present;
-                    if (entry.active > 0)
-                        ++active;
-                }
-            }
-        }
-        return String.format("%s@%x[c=%d/%d/%d,a=%d]",
-            getClass().getSimpleName(),
-            hashCode(),
-            getPendingConnectionCount(),
-            present,
-            getMaxConnectionCount(),
-            active
-        );
-    }
-
-    private static class Entry
-    {
-        private Connection connection;
-        private int active;
-        private long used;
-
-        private void reset()
-        {
-            connection = null;
-            active = 0;
-            used = 0;
-        }
-
-        @Override
-        public String toString()
-        {
-            return String.format("{u=%d,c=%s}", used, connection);
+            Connection connection = entry.getPooled();
+            acquired(connection);
+            return connection;
         }
+        return null;
     }
 }

jetty-client/src/main/java/org/eclipse/jetty/client/ValidatingConnectionPool.java

@@ -19,15 +19,15 @@
 package org.eclipse.jetty.client;
 
 import java.io.IOException;
-import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.stream.Stream;
 
 import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
+import org.eclipse.jetty.util.component.Dumpable;
 import org.eclipse.jetty.util.component.DumpableCollection;
 import org.eclipse.jetty.util.thread.Scheduler;
 import org.slf4j.Logger;
@@ -66,10 +66,10 @@ public class ValidatingConnectionPool extends DuplexConnectionPool
 
     public ValidatingConnectionPool(HttpDestination destination, int maxConnections, Callback requester, Scheduler scheduler, long timeout)
     {
-        super(destination, maxConnections, requester);
+        super((HttpDestination)destination, maxConnections, requester);
         this.scheduler = scheduler;
         this.timeout = timeout;
-        this.quarantine = new HashMap<>(maxConnections);
+        this.quarantine = new ConcurrentHashMap<>(maxConnections);
     }
 
     @ManagedAttribute(value = "The number of validating connections", readonly = true)
@@ -81,21 +81,11 @@ public class ValidatingConnectionPool extends DuplexConnectionPool
     @Override
     public boolean release(Connection connection)
     {
-        lock();
-        try
-        {
-            if (!getActiveConnections().remove(connection))
-                return false;
-            Holder holder = new Holder(connection);
-            holder.task = scheduler.schedule(holder, timeout, TimeUnit.MILLISECONDS);
-            quarantine.put(connection, holder);
-            if (LOG.isDebugEnabled())
-                LOG.debug("Validating for {}ms {}", timeout, connection);
-        }
-        finally
-        {
-            unlock();
-        }
+        Holder holder = new Holder(connection);
+        holder.task = scheduler.schedule(holder, timeout, TimeUnit.MILLISECONDS);
+        quarantine.put(connection, holder);
+        if (LOG.isDebugEnabled())
+            LOG.debug("Validating for {}ms {}", timeout, connection);
 
         released(connection);
         return true;
@@ -104,16 +94,7 @@ public class ValidatingConnectionPool extends DuplexConnectionPool
     @Override
     public boolean remove(Connection connection)
     {
-        Holder holder;
-        lock();
-        try
-        {
-            holder = quarantine.remove(connection);
-        }
-        finally
-        {
-            unlock();
-        }
+        Holder holder = quarantine.remove(connection);
 
         if (holder == null)
             return super.remove(connection);
@@ -129,25 +110,16 @@ public class ValidatingConnectionPool extends DuplexConnectionPool
     }
 
     @Override
-    protected void dump(Appendable out, String indent, Object... items) throws IOException
+    public void dump(Appendable out, String indent) throws IOException
     {
         DumpableCollection toDump = new DumpableCollection("quarantine", quarantine.values());
-        super.dump(out, indent, Stream.concat(Stream.of(items), Stream.of(toDump)));
+        Dumpable.dumpObjects(out, indent, this, toDump);
     }
 
     @Override
     public String toString()
     {
-        int size;
-        lock();
-        try
-        {
-            size = quarantine.size();
-        }
-        finally
-        {
-            unlock();
-        }
+        int size = quarantine.size();
         return String.format("%s[v=%d]", super.toString(), size);
     }
 
@@ -169,20 +141,11 @@ public class ValidatingConnectionPool extends DuplexConnectionPool
             if (done.compareAndSet(false, true))
             {
                 boolean closed = isClosed();
-                lock();
-                try
-                {
-                    if (LOG.isDebugEnabled())
-                        LOG.debug("Validated {}", connection);
-                    quarantine.remove(connection);
-                    if (!closed)
-                        deactivate(connection);
-                }
-                finally
-                {
-                    unlock();
-                }
-
+                if (LOG.isDebugEnabled())
+                    LOG.debug("Validated {}", connection);
+                quarantine.remove(connection);
+                if (!closed)
+                    deactivate(connection);
                 idle(connection, closed);
                 proceed();
             }

jetty-client/src/main/java/org/eclipse/jetty/client/http/HttpConnectionOverHTTP.java

@@ -44,12 +44,13 @@ import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.io.AbstractConnection;
 import org.eclipse.jetty.io.EndPoint;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.Promise;
 import org.eclipse.jetty.util.thread.Sweeper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class HttpConnectionOverHTTP extends AbstractConnection implements IConnection, org.eclipse.jetty.io.Connection.UpgradeFrom, Sweeper.Sweepable
+public class HttpConnectionOverHTTP extends AbstractConnection implements IConnection, org.eclipse.jetty.io.Connection.UpgradeFrom, Sweeper.Sweepable, Attachable
 {
     private static final Logger LOG = LoggerFactory.getLogger(HttpConnectionOverHTTP.class);
 
@@ -161,6 +162,18 @@ public class HttpConnectionOverHTTP extends AbstractConnection implements IConne
         return closed.get();
     }
 
+    @Override
+    public void setAttachment(Object obj)
+    {
+        delegate.setAttachment(obj);
+    }
+
+    @Override
+    public Object getAttachment()
+    {
+        return delegate.getAttachment();
+    }
+
     @Override
     public boolean onIdleExpired()
     {

jetty-client/src/test/java/org/eclipse/jetty/client/ConnectionPoolHelper.java

@@ -0,0 +1,34 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.client;
+
+import org.eclipse.jetty.client.api.Connection;
+
+public class ConnectionPoolHelper
+{
+    public static Connection acquire(AbstractConnectionPool connectionPool, boolean create)
+    {
+        return connectionPool.acquire(create);
+    }
+
+    public static void tryCreate(AbstractConnectionPool connectionPool, int pending)
+    {
+        connectionPool.tryCreate(pending);
+    }
+}

jetty-client/src/test/java/org/eclipse/jetty/client/DuplexHttpDestinationTest.java

@@ -16,7 +16,7 @@
 // ========================================================================
 //
 
-package org.eclipse.jetty.client.http;
+package org.eclipse.jetty.client;
 
 import java.lang.reflect.Method;
 import java.util.concurrent.CountDownLatch;
@@ -24,21 +24,12 @@ import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 
-import org.eclipse.jetty.client.AbstractHttpClientServerTest;
-import org.eclipse.jetty.client.ConnectionPool;
-import org.eclipse.jetty.client.DuplexConnectionPool;
-import org.eclipse.jetty.client.DuplexHttpDestination;
-import org.eclipse.jetty.client.EmptyServerHandler;
-import org.eclipse.jetty.client.HttpClient;
-import org.eclipse.jetty.client.HttpDestination;
-import org.eclipse.jetty.client.Origin;
 import org.eclipse.jetty.client.api.Connection;
 import org.eclipse.jetty.client.api.ContentResponse;
 import org.eclipse.jetty.client.api.Destination;
 import org.eclipse.jetty.client.api.Request;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpHeaderValue;
-import org.eclipse.jetty.util.Callback;
 import org.hamcrest.Matchers;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ArgumentsSource;
@@ -52,7 +43,7 @@ import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
+public class DuplexHttpDestinationTest extends AbstractHttpClientServerTest
 {
     @ParameterizedTest
     @ArgumentsSource(ScenarioProvider.class)
@@ -67,7 +58,7 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
             Connection connection = connectionPool.acquire(true);
             assertNull(connection);
             // There are no queued requests, so no connection should be created.
-            connection = pollIdleConnection(connectionPool, 1, TimeUnit.SECONDS);
+            connection = peekIdleConnection(connectionPool, 1, TimeUnit.SECONDS);
             assertNull(connection);
         }
     }
@@ -78,19 +69,19 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
     {
         start(scenario, new EmptyServerHandler());
 
-        try (TestDestination destination = new TestDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
+        try (HttpDestination destination = new DuplexHttpDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
         {
             destination.start();
-            TestDestination.TestConnectionPool connectionPool = (TestDestination.TestConnectionPool)destination.getConnectionPool();
+            DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
             // Trigger creation of one connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
-            Connection connection = connectionPool.acquire(false);
+            Connection connection = ConnectionPoolHelper.acquire(connectionPool, false);
             if (connection == null)
             {
                 // There are no queued requests, so the newly created connection will be idle
-                connection = pollIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
+                connection = peekIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
             }
             assertNotNull(connection);
         }
@@ -102,13 +93,13 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
     {
         start(scenario, new EmptyServerHandler());
 
-        try (TestDestination destination = new TestDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
+        try (HttpDestination destination = new DuplexHttpDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
         {
             destination.start();
-            TestDestination.TestConnectionPool connectionPool = (TestDestination.TestConnectionPool)destination.getConnectionPool();
+            DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
             // Trigger creation of one connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
             Connection connection1 = connectionPool.acquire(true);
             if (connection1 == null)
@@ -131,12 +122,12 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
 
         CountDownLatch idleLatch = new CountDownLatch(1);
         CountDownLatch latch = new CountDownLatch(1);
-        try (TestDestination destination = new TestDestination(client, new Origin("http", "localhost", connector.getLocalPort()))
+        try (HttpDestination destination = new DuplexHttpDestination(client, new Origin("http", "localhost", connector.getLocalPort()))
         {
             @Override
             protected ConnectionPool newConnectionPool(HttpClient client)
             {
-                return new TestConnectionPool(this, client.getMaxConnectionsPerDestination(), this)
+                return new DuplexConnectionPool(this, client.getMaxConnectionsPerDestination(), this)
                 {
                     @Override
                     protected void onCreated(Connection connection)
@@ -157,10 +148,10 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
         })
         {
             destination.start();
-            TestDestination.TestConnectionPool connectionPool = (TestDestination.TestConnectionPool)destination.getConnectionPool();
+            DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
             // Trigger creation of one connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
             // Make sure we entered idleCreated().
             assertTrue(idleLatch.await(5, TimeUnit.SECONDS));
@@ -171,7 +162,7 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
             assertNull(connection1);
 
             // Trigger creation of a second connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
             // Second attempt also returns null because we delayed idleCreated() above.
             Connection connection2 = connectionPool.acquire(true);
@@ -180,9 +171,9 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
             latch.countDown();
 
             // There must be 2 idle connections.
-            Connection connection = pollIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
+            Connection connection = peekIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
             assertNotNull(connection);
-            connection = pollIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
+            connection = peekIdleConnection(connectionPool, 5, TimeUnit.SECONDS);
             assertNotNull(connection);
         }
     }
@@ -193,13 +184,13 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
     {
         start(scenario, new EmptyServerHandler());
 
-        try (TestDestination destination = new TestDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
+        try (HttpDestination destination = new DuplexHttpDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
         {
             destination.start();
-            TestDestination.TestConnectionPool connectionPool = (TestDestination.TestConnectionPool)destination.getConnectionPool();
+            DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
             // Trigger creation of one connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
             Connection connection1 = connectionPool.acquire(true);
             if (connection1 == null)
@@ -230,13 +221,13 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
         long idleTimeout = 1000;
         startClient(scenario, httpClient -> httpClient.setIdleTimeout(idleTimeout));
 
-        try (TestDestination destination = new TestDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
+        try (HttpDestination destination = new DuplexHttpDestination(client, new Origin("http", "localhost", connector.getLocalPort())))
         {
             destination.start();
-            TestDestination.TestConnectionPool connectionPool = (TestDestination.TestConnectionPool)destination.getConnectionPool();
+            DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
             // Trigger creation of one connection.
-            connectionPool.tryCreate(1);
+            ConnectionPoolHelper.tryCreate(connectionPool, 1);
 
             Connection connection1 = connectionPool.acquire(true);
             if (connection1 == null)
@@ -247,7 +238,7 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
 
                 TimeUnit.MILLISECONDS.sleep(2 * idleTimeout);
 
-                connection1 = connectionPool.getIdleConnections().poll();
+                connection1 = connectionPool.getIdleConnections().peek();
                 assertNull(connection1);
             }
         }
@@ -353,11 +344,6 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
         assertTrue(client.getDestinations().isEmpty(), "Destination must be removed after connection error");
     }
 
-    private Connection pollIdleConnection(DuplexConnectionPool connectionPool, long time, TimeUnit unit) throws InterruptedException
-    {
-        return await(() -> connectionPool.getIdleConnections().poll(), time, unit);
-    }
-
     private Connection peekIdleConnection(DuplexConnectionPool connectionPool, long time, TimeUnit unit) throws InterruptedException
     {
         return await(() -> connectionPool.getIdleConnections().peek(), time, unit);
@@ -375,38 +361,4 @@ public class HttpDestinationOverHTTPTest extends AbstractHttpClientServerTest
         }
         return null;
     }
-
-    private static class TestDestination extends DuplexHttpDestination
-    {
-        public TestDestination(HttpClient client, Origin origin)
-        {
-            super(client, origin);
-        }
-
-        @Override
-        protected ConnectionPool newConnectionPool(HttpClient client)
-        {
-            return new TestConnectionPool(this, client.getMaxConnectionsPerDestination(), this);
-        }
-
-        public static class TestConnectionPool extends DuplexConnectionPool
-        {
-            public TestConnectionPool(HttpDestination destination, int maxConnections, Callback requester)
-            {
-                super(destination, maxConnections, requester);
-            }
-
-            @Override
-            public void tryCreate(int maxPending)
-            {
-                super.tryCreate(maxPending);
-            }
-
-            @Override
-            public Connection acquire(boolean create)
-            {
-                return super.acquire(create);
-            }
-        }
-    }
 }

jetty-client/src/test/java/org/eclipse/jetty/client/HttpClientTLSTest.java

@@ -661,7 +661,7 @@ public class HttpClientTLSTest
         HttpDestination destination = client.resolveDestination(origin);
         DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
         // Trigger the creation of a new connection, but don't use it.
-        connectionPool.tryCreate(-1);
+        ConnectionPoolHelper.tryCreate(connectionPool, -1);
         // Verify that the connection has been created.
         while (true)
         {
@@ -759,7 +759,7 @@ public class HttpClientTLSTest
         HttpDestination destination = client.resolveDestination(origin);
         DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
         // Trigger the creation of a new connection, but don't use it.
-        connectionPool.tryCreate(-1);
+        ConnectionPoolHelper.tryCreate(connectionPool, -1);
         // Verify that the connection has been created.
         while (true)
         {

jetty-client/src/test/java/org/eclipse/jetty/client/HttpConnectionLifecycleTest.java

@@ -74,17 +74,14 @@ public class HttpConnectionLifecycleTest extends AbstractHttpClientServerTest
         HttpDestination destination = (HttpDestination)client.resolveDestination(request);
         DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
-        Collection<Connection> idleConnections = connectionPool.getIdleConnections();
-        assertEquals(0, idleConnections.size());
-
-        Collection<Connection> activeConnections = connectionPool.getActiveConnections();
-        assertEquals(0, activeConnections.size());
+        assertEquals(0, connectionPool.getIdleConnections().size());
+        assertEquals(0, connectionPool.getActiveConnections().size());
 
         request.onRequestSuccess(r -> successLatch.countDown())
             .onResponseHeaders(response ->
             {
-                assertEquals(0, idleConnections.size());
-                assertEquals(1, activeConnections.size());
+                assertEquals(0, ((DuplexConnectionPool)destination.getConnectionPool()).getIdleConnections().size());
+                assertEquals(1, ((DuplexConnectionPool)destination.getConnectionPool()).getActiveConnections().size());
                 headersLatch.countDown();
             })
             .send(new Response.Listener.Adapter()
@@ -106,8 +103,8 @@ public class HttpConnectionLifecycleTest extends AbstractHttpClientServerTest
         assertTrue(headersLatch.await(30, TimeUnit.SECONDS));
         assertTrue(successLatch.await(30, TimeUnit.SECONDS));
 
-        assertEquals(1, idleConnections.size());
-        assertEquals(0, activeConnections.size());
+        assertEquals(1, ((DuplexConnectionPool)destination.getConnectionPool()).getIdleConnections().size());
+        assertEquals(0, ((DuplexConnectionPool)destination.getConnectionPool()).getActiveConnections().size());
     }
 
     @ParameterizedTest
@@ -124,18 +121,15 @@ public class HttpConnectionLifecycleTest extends AbstractHttpClientServerTest
         HttpDestination destination = (HttpDestination)client.resolveDestination(request);
         DuplexConnectionPool connectionPool = (DuplexConnectionPool)destination.getConnectionPool();
 
-        Collection<Connection> idleConnections = connectionPool.getIdleConnections();
-        assertEquals(0, idleConnections.size());
-
-        Collection<Connection> activeConnections = connectionPool.getActiveConnections();
-        assertEquals(0, activeConnections.size());
+        assertEquals(0, connectionPool.getIdleConnections().size());
+        assertEquals(0, connectionPool.getActiveConnections().size());
 
         request.listener(new Request.Listener.Adapter()
         {
             @Override
             public void onBegin(Request request)
             {
-                activeConnections.iterator().next().close();
+                connectionPool.getActiveConnections().iterator().next().close();
                 beginLatch.countDown();
             }
 
@@ -144,24 +138,23 @@ public class HttpConnectionLifecycleTest extends AbstractHttpClientServerTest
             {
                 failureLatch.countDown();
             }
-        })
-            .send(new Response.Listener.Adapter()
+        }).send(new Response.Listener.Adapter()
+        {
+            @Override
+            public void onComplete(Result result)
             {
-                @Override
-                public void onComplete(Result result)
-                {
-                    assertTrue(result.isFailed());
-                    assertEquals(0, idleConnections.size());
-                    assertEquals(0, activeConnections.size());
-                    failureLatch.countDown();
-                }
-            });
+                assertTrue(result.isFailed());
+                assertEquals(0, connectionPool.getIdleConnections().size());
+                assertEquals(0, connectionPool.getActiveConnections().size());
+                failureLatch.countDown();
+            }
+        });
 
         assertTrue(beginLatch.await(30, TimeUnit.SECONDS));
         assertTrue(failureLatch.await(30, TimeUnit.SECONDS));
 
-        assertEquals(0, idleConnections.size());
-        assertEquals(0, activeConnections.size());
+        assertEquals(0, connectionPool.getIdleConnections().size());
+        assertEquals(0, connectionPool.getActiveConnections().size());
     }
 
     @ParameterizedTest

jetty-fcgi/fcgi-client/src/main/java/org/eclipse/jetty/fcgi/client/http/HttpConnectionOverFCGI.java

@@ -51,6 +51,7 @@ import org.eclipse.jetty.io.AbstractConnection;
 import org.eclipse.jetty.io.ByteBufferPool;
 import org.eclipse.jetty.io.EndPoint;
 import org.eclipse.jetty.io.RetainableByteBuffer;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.BufferUtil;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.Promise;
@@ -58,7 +59,7 @@ import org.eclipse.jetty.util.thread.AutoLock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-public class HttpConnectionOverFCGI extends AbstractConnection implements IConnection
+public class HttpConnectionOverFCGI extends AbstractConnection implements IConnection, Attachable
 {
     private static final Logger LOG = LoggerFactory.getLogger(HttpConnectionOverFCGI.class);
 
@@ -73,6 +74,7 @@ public class HttpConnectionOverFCGI extends AbstractConnection implements IConne
     private final Delegate delegate;
     private final ClientParser parser;
     private RetainableByteBuffer networkBuffer;
+    private Object attachment;
 
     public HttpConnectionOverFCGI(EndPoint endPoint, HttpDestination destination, Promise<Connection> promise)
     {
@@ -267,6 +269,18 @@ public class HttpConnectionOverFCGI extends AbstractConnection implements IConne
         return closed.get();
     }
 
+    @Override
+    public void setAttachment(Object obj)
+    {
+        this.attachment = obj;
+    }
+
+    @Override
+    public Object getAttachment()
+    {
+        return attachment;
+    }
+
     protected boolean closeByHTTP(HttpFields fields)
     {
         if (!fields.contains(HttpHeader.CONNECTION, HttpHeaderValue.CLOSE.asString()))

jetty-http2/http2-common/src/main/java/org/eclipse/jetty/http2/IStream.java

@@ -22,6 +22,7 @@ import java.io.Closeable;
 
 import org.eclipse.jetty.http2.api.Stream;
 import org.eclipse.jetty.http2.frames.Frame;
+import org.eclipse.jetty.util.Attachable;
 import org.eclipse.jetty.util.Callback;
 
 /**
@@ -29,21 +30,8 @@ import org.eclipse.jetty.util.Callback;
  * <p>This class extends {@link Stream} by adding the methods required to
  * implement the HTTP/2 stream functionalities.</p>
  */
-public interface IStream extends Stream, Closeable
+public interface IStream extends Stream, Attachable, Closeable
 {
-    /**
-     * @return the object attached to this stream
-     * @see #setAttachment(Object)
-     */
-    public Object getAttachment();
-
-    /**
-     * Attaches the given object to this stream for later retrieval.
-     *
-     * @param attachment the object to attach to this stream
-     */
-    public void setAttachment(Object attachment);
-
     /**
      * @return whether this stream is local or remote
      */

jetty-openid/src/main/java/org/eclipse/jetty/security/openid/OpenIdCredentials.java

@@ -72,24 +72,6 @@ public class OpenIdCredentials implements Serializable
         return response;
     }
 
-    public boolean isExpired()
-    {
-        if (authCode != null || claims == null)
-            return true;
-
-        // Check expiry
-        long expiry = (Long)claims.get("exp");
-        long currentTimeSeconds = (long)(System.currentTimeMillis() / 1000F);
-        if (currentTimeSeconds > expiry)
-        {
-            if (LOG.isDebugEnabled())
-                LOG.debug("OpenId Credentials expired {}", this);
-            return true;
-        }
-
-        return false;
-    }
-
     public void redeemAuthCode(OpenIdConfiguration configuration) throws Exception
     {
         if (LOG.isDebugEnabled())
@@ -105,15 +87,15 @@ public class OpenIdCredentials implements Serializable
 
                 String idToken = (String)response.get("id_token");
                 if (idToken == null)
-                    throw new IllegalArgumentException("no id_token");
+                    throw new AuthenticationException("no id_token");
 
                 String accessToken = (String)response.get("access_token");
                 if (accessToken == null)
-                    throw new IllegalArgumentException("no access_token");
+                    throw new AuthenticationException("no access_token");
 
                 String tokenType = (String)response.get("token_type");
                 if (!"Bearer".equalsIgnoreCase(tokenType))
-                    throw new IllegalArgumentException("invalid token_type");
+                    throw new AuthenticationException("invalid token_type");
 
                 claims = JwtDecoder.decode(idToken);
                 if (LOG.isDebugEnabled())
@@ -128,11 +110,11 @@ public class OpenIdCredentials implements Serializable
         }
     }
 
-    private void validateClaims(OpenIdConfiguration configuration)
+    private void validateClaims(OpenIdConfiguration configuration) throws Exception
     {
         // Issuer Identifier for the OpenID Provider MUST exactly match the value of the iss (issuer) Claim.
         if (!configuration.getIssuer().equals(claims.get("iss")))
-            throw new IllegalArgumentException("Issuer Identifier MUST exactly match the iss Claim");
+            throw new AuthenticationException("Issuer Identifier MUST exactly match the iss Claim");
 
         // The aud (audience) Claim MUST contain the client_id value.
         validateAudience(configuration);
@@ -140,10 +122,16 @@ public class OpenIdCredentials implements Serializable
         // If an azp (authorized party) Claim is present, verify that its client_id is the Claim Value.
         Object azp = claims.get("azp");
         if (azp != null && !configuration.getClientId().equals(azp))
-            throw new IllegalArgumentException("Authorized party claim value should be the client_id");
+            throw new AuthenticationException("Authorized party claim value should be the client_id");
+
+        // Check that the ID token has not expired by checking the exp claim.
+        long expiry = (Long)claims.get("exp");
+        long currentTimeSeconds = (long)(System.currentTimeMillis() / 1000F);
+        if (currentTimeSeconds > expiry)
+            throw new AuthenticationException("ID Token has expired");
     }
 
-    private void validateAudience(OpenIdConfiguration configuration)
+    private void validateAudience(OpenIdConfiguration configuration) throws AuthenticationException
     {
         Object aud = claims.get("aud");
         String clientId = configuration.getClientId();
@@ -152,17 +140,17 @@ public class OpenIdCredentials implements Serializable
         boolean isValidType = isString || isList;
 
         if (isString && !clientId.equals(aud))
-            throw new IllegalArgumentException("Audience Claim MUST contain the client_id value");
+            throw new AuthenticationException("Audience Claim MUST contain the client_id value");
         else if (isList)
         {
             if (!Arrays.asList((Object[])aud).contains(clientId))
-                throw new IllegalArgumentException("Audience Claim MUST contain the client_id value");
+                throw new AuthenticationException("Audience Claim MUST contain the client_id value");
 
             if (claims.get("azp") == null)
-                throw new IllegalArgumentException("A multi-audience ID token needs to contain an azp claim");
+                throw new AuthenticationException("A multi-audience ID token needs to contain an azp claim");
         }
         else if (!isValidType)
-            throw new IllegalArgumentException("Audience claim was not valid");
+            throw new AuthenticationException("Audience claim was not valid");
     }
 
     @SuppressWarnings("unchecked")
@@ -185,7 +173,15 @@ public class OpenIdCredentials implements Serializable
 
         Object parsedResponse = new JSON().fromJSON(responseBody);
         if (!(parsedResponse instanceof Map))
-            throw new IllegalStateException("Malformed response from OpenID Provider");
+            throw new AuthenticationException("Malformed response from OpenID Provider");
         return (Map<String, Object>)parsedResponse;
     }
+
+    public static class AuthenticationException extends Exception
+    {
+        public AuthenticationException(String message)
+        {
+            super(message);
+        }
+    }
 }

jetty-openid/src/main/java/org/eclipse/jetty/security/openid/OpenIdLoginService.java

@@ -18,7 +18,6 @@
 
 package org.eclipse.jetty.security.openid;
 
-import java.security.Principal;
 import javax.security.auth.Subject;
 import javax.servlet.ServletRequest;
 
@@ -86,8 +85,6 @@ public class OpenIdLoginService extends ContainerLifeCycle implements LoginServi
         try
         {
             openIdCredentials.redeemAuthCode(configuration);
-            if (openIdCredentials.isExpired())
-                return null;
         }
         catch (Throwable e)
         {
@@ -138,12 +135,10 @@ public class OpenIdLoginService extends ContainerLifeCycle implements LoginServi
     @Override
     public boolean validate(UserIdentity user)
     {
-        Principal userPrincipal = user.getUserPrincipal();
-        if (!(userPrincipal instanceof OpenIdUserPrincipal))
+        if (!(user.getUserPrincipal() instanceof OpenIdUserPrincipal))
             return false;
 
-        OpenIdCredentials credentials = ((OpenIdUserPrincipal)userPrincipal).getCredentials();
-        return !credentials.isExpired();
+        return loginService == null || loginService.validate(user);
     }
 
     @Override
@@ -167,5 +162,7 @@ public class OpenIdLoginService extends ContainerLifeCycle implements LoginServi
     @Override
     public void logout(UserIdentity user)
     {
+        if (loginService != null)
+            loginService.logout(user);
     }
 }

jetty-server/src/main/java/org/eclipse/jetty/server/Dispatcher.java

@@ -410,7 +410,7 @@ public class Dispatcher implements RequestDispatcher
                     case INCLUDE_CONTEXT_PATH:
                     {
                         ContextHandler.Context context = _baseRequest.getContext();
-                        return context == null ? null : context.getContextHandler().getContextPathEncoded();
+                        return context == null ? null : context.getContextHandler().getRequestContextPath();
                     }
                     case INCLUDE_QUERY_STRING:
                         return _query;

jetty-server/src/main/java/org/eclipse/jetty/server/Request.java

@@ -794,14 +794,7 @@ public class Request implements HttpServletRequest
         if (context == null)
             return null;
 
-        // For some reason the spec requires the context path to be encoded (unlike getServletPath).
-        String contextPath = context.getContextHandler().getContextPathEncoded();
-
-        // For the root context, the spec requires that the empty string is returned instead of the leading '/'
-        // which is included in the pathInContext
-        if (URIUtil.SLASH.equals(contextPath))
-            return "";
-        return contextPath;
+        return context.getContextHandler().getRequestContextPath();
     }
 
     /** Get the path in the context.
@@ -1714,7 +1707,7 @@ public class Request implements HttpServletRequest
             // TODO this is not really right for CONNECT
             path = _uri.isAbsolute() ? "/" : null;
         else if (encoded.startsWith("/"))
-            path = (encoded.length() == 1) ? "/" : _uri.getDecodedPath();
+            path = (encoded.length() == 1) ? "/" : URIUtil.canonicalPath(_uri.getDecodedPath());
         else if ("*".equals(encoded) || HttpMethod.CONNECT.is(getMethod()))
             path = encoded;
         else

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java

@@ -41,6 +41,7 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.servlet.DispatcherType;
 import javax.servlet.Filter;
 import javax.servlet.FilterRegistration;
@@ -225,11 +226,14 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
 
     public enum Availability
     {
-        UNAVAILABLE, STARTING, AVAILABLE, SHUTDOWN,
+        STOPPED,        // stopped and can't be made unavailable nor shutdown
+        STARTING,       // starting inside of doStart. It may go to any of the next states.
+        AVAILABLE,      // running normally
+        UNAVAILABLE,    // Either a startup error or explicit call to setAvailable(false)
+        SHUTDOWN,       // graceful shutdown
     }
 
-    ;
-    private volatile Availability _availability = Availability.UNAVAILABLE;
+    private final AtomicReference<Availability> _availability = new AtomicReference<>(Availability.STOPPED);
 
     public ContextHandler()
     {
@@ -727,7 +731,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     @ManagedAttribute("true for graceful shutdown, which allows existing requests to complete")
     public boolean isShutdown()
     {
-        return _availability == Availability.SHUTDOWN;
+        return _availability.get() == Availability.SHUTDOWN;
     }
 
     /**
@@ -737,10 +741,25 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     @Override
     public CompletableFuture<Void> shutdown()
     {
-        _availability = isRunning() ? Availability.SHUTDOWN : Availability.UNAVAILABLE;
-        CompletableFuture<Void> shutdown = new CompletableFuture<Void>();
-        shutdown.complete(null);
-        return shutdown;
+        while (true)
+        {
+            Availability availability = _availability.get();
+            switch (availability)
+            {
+                case STOPPED:
+                    return CompletableFuture.failedFuture(new IllegalStateException(getState()));
+                case STARTING:
+                case AVAILABLE:
+                case UNAVAILABLE:
+                    if (!_availability.compareAndSet(availability, Availability.SHUTDOWN))
+                        continue;
+                    break;
+                default:
+                    break;
+            }
+            break;
+        }
+        return CompletableFuture.completedFuture(null);
     }
 
     /**
@@ -748,7 +767,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
      */
     public boolean isAvailable()
     {
-        return _availability == Availability.AVAILABLE;
+        return _availability.get() == Availability.AVAILABLE;
     }
 
     /**
@@ -758,12 +777,46 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
      */
     public void setAvailable(boolean available)
     {
-        try (AutoLock l = _lock.lock())
+        // Only supported state transitions are:
+        //   UNAVAILABLE --true---> AVAILABLE
+        //   STARTING -----false--> UNAVAILABLE
+        //   AVAILABLE ----false--> UNAVAILABLE
+        if (available)
         {
-            if (available && isRunning())
-                _availability = Availability.AVAILABLE;
-            else if (!available || !isRunning())
-                _availability = Availability.UNAVAILABLE;
+            while (true)
+            {
+                Availability availability = _availability.get();
+                switch (availability)
+                {
+                    case AVAILABLE:
+                        break;
+                    case UNAVAILABLE:
+                        if (!_availability.compareAndSet(availability, Availability.AVAILABLE))
+                            continue;
+                        break;
+                    default:
+                        throw new IllegalStateException(availability.toString());
+                }
+                break;
+            }
+        }
+        else
+        {
+            while (true)
+            {
+                Availability availability = _availability.get();
+                switch (availability)
+                {
+                    case STARTING:
+                    case AVAILABLE:
+                        if (!_availability.compareAndSet(availability, Availability.UNAVAILABLE))
+                            continue;
+                        break;
+                    default:
+                        break;
+                }
+                break;
+            }
         }
     }
 
@@ -780,7 +833,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     @Override
     protected void doStart() throws Exception
     {
-        _availability = Availability.STARTING;
+        _availability.set(Availability.STARTING);
 
         if (_contextPath == null)
             throw new IllegalStateException("Null contextPath");
@@ -817,13 +870,12 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             
             contextInitialized();
 
-            _availability = Availability.AVAILABLE;
+            _availability.compareAndSet(Availability.STARTING, Availability.AVAILABLE);
             LOG.info("Started {}", this);
         }
         finally
         {
-            if (_availability == Availability.STARTING)
-                _availability = Availability.UNAVAILABLE;
+            _availability.compareAndSet(Availability.STARTING, Availability.UNAVAILABLE);
             exitScope(null);
             __context.set(oldContext);
             // reset the classloader
@@ -971,7 +1023,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     {
         if (getServer().isDryRun())
             return;
-        
+
         if (LOG.isDebugEnabled())
             LOG.debug("contextInitialized: {}->{}", e, l);
         l.contextInitialized(e);
@@ -981,7 +1033,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     {
         if (getServer().isDryRun())
             return;
-        
+
         if (LOG.isDebugEnabled())
             LOG.debug("contextDestroyed: {}->{}", e, l);
         l.contextDestroyed(e);
@@ -993,7 +1045,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         // Should we attempt a graceful shutdown?
         MultiException mex = null;
 
-        _availability = Availability.UNAVAILABLE;
+        _availability.set(Availability.STOPPED);
 
         ClassLoader oldClassloader = null;
         ClassLoader oldWebapploader = null;
@@ -1148,8 +1200,10 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             return false;
         }
 
-        switch (_availability)
+        switch (_availability.get())
         {
+            case STOPPED:
+                return false;
             case SHUTDOWN:
             case UNAVAILABLE:
                 baseRequest.setHandled(true);
@@ -1504,6 +1558,8 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
      */
     public void setClassLoader(ClassLoader classLoader)
     {
+        if (isStarted())
+            throw new IllegalStateException(getState());
         _classLoader = classLoader;
     }
 
@@ -1776,7 +1832,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         b.append('{');
         if (getDisplayName() != null)
             b.append(getDisplayName()).append(',');
-        b.append(getContextPath()).append(',').append(getBaseResource()).append(',').append(_availability);
+        b.append(getContextPath()).append(',').append(getBaseResource()).append(',').append(_availability.get());
 
         if (vhosts != null && vhosts.length > 0)
             b.append(',').append(vhosts[0]);

jetty-server/src/test/java/org/eclipse/jetty/server/LargeHeaderTest.java

@@ -37,8 +37,6 @@ import org.eclipse.jetty.server.handler.AbstractHandler;
 import org.eclipse.jetty.server.handler.ErrorHandler;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.component.LifeCycle;
-import org.eclipse.jetty.util.log.Log;
-import org.eclipse.jetty.util.log.Logger;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -100,7 +98,6 @@ public class LargeHeaderTest
     @Test
     public void testLargeHeader() throws Throwable
     {
-        final Logger CLIENTLOG = Log.getLogger(LargeHeaderTest.class).getLogger(".client");
         ExecutorService executorService = Executors.newFixedThreadPool(8);
 
         int localPort = server.getURI().getPort();
@@ -127,7 +124,6 @@ public class LargeHeaderTest
                 }
                 catch (Throwable t)
                 {
-                    CLIENTLOG.warn("Client Issue", t);
                     issues.addSuppressed(t);
                 }
             });

jetty-server/src/test/java/org/eclipse/jetty/server/handler/ContextHandlerTest.java

@@ -417,6 +417,18 @@ public class ContextHandlerTest
         assertThat(connector.getResponse("GET /foo/xxx HTTP/1.0\n\n"), Matchers.containsString("ctx='/foo'"));
         assertThat(connector.getResponse("GET /foo/bar/xxx HTTP/1.0\n\n"), Matchers.containsString("ctx='/foo/bar'"));
 
+        // If we make foobar unavailable, then requests will be handled by 503
+        foobar.setAvailable(false);
+        assertThat(connector.getResponse("GET / HTTP/1.0\n\n"), Matchers.containsString("ctx=''"));
+        assertThat(connector.getResponse("GET /foo/xxx HTTP/1.0\n\n"), Matchers.containsString("ctx='/foo'"));
+        assertThat(connector.getResponse("GET /foo/bar/xxx HTTP/1.0\n\n"), Matchers.containsString(" 503 "));
+
+        // If we make foobar available, then requests will be handled normally
+        foobar.setAvailable(true);
+        assertThat(connector.getResponse("GET / HTTP/1.0\n\n"), Matchers.containsString("ctx=''"));
+        assertThat(connector.getResponse("GET /foo/xxx HTTP/1.0\n\n"), Matchers.containsString("ctx='/foo'"));
+        assertThat(connector.getResponse("GET /foo/bar/xxx HTTP/1.0\n\n"), Matchers.containsString("ctx='/foo/bar'"));
+
         // If we stop foobar, then requests will be handled by foo
         foobar.stop();
         assertThat(connector.getResponse("GET / HTTP/1.0\n\n"), Matchers.containsString("ctx=''"));

jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHandler.java

@@ -450,8 +450,6 @@ public class ServletHandler extends ScopedHandler
         // Get the base requests
         final ServletPathMapping old_servlet_path_mapping = baseRequest.getServletPathMapping();
 
-        DispatcherType type = baseRequest.getDispatcherType();
-
         ServletHolder servletHolder = null;
         UserIdentity.Scope oldScope = null;
 
@@ -483,8 +481,7 @@ public class ServletHandler extends ScopedHandler
             if (oldScope != null)
                 baseRequest.setUserIdentityScope(oldScope);
 
-            if (!(DispatcherType.INCLUDE.equals(type)))
-                baseRequest.setServletPathMapping(old_servlet_path_mapping);
+            baseRequest.setServletPathMapping(old_servlet_path_mapping);
         }
     }
 

jetty-servlet/src/test/java/org/eclipse/jetty/servlet/DefaultServletRangesTest.java

@@ -150,12 +150,28 @@ public class DefaultServletRangesTest
         String boundary = body.substring(0, body.indexOf("\r\n"));
         assertResponseContains("206 Partial", response);
         assertResponseContains("Content-Type: multipart/byteranges; boundary=", response);
-        assertResponseContains("Content-Range: bytes 0-9/80", response);
-        assertResponseContains("Content-Range: bytes 20-29/80", response);
-        assertResponseContains("Content-Range: bytes 40-49/80", response);
-        assertResponseContains(DATA.substring(0, 10), response);
-        assertResponseContains(DATA.substring(20, 30), response);
-        assertResponseContains(DATA.substring(40, 50), response);
+
+        String section1 = boundary + "\r\n" +
+            "Content-Type: text/plain\r\n" +
+            "Content-Range: bytes 0-9/80\r\n" +
+            "\r\n" +
+            DATA.substring(0, 10) + "\r\n";
+        assertResponseContains(section1, response);
+
+        String section2 = boundary + "\r\n" +
+            "Content-Type: text/plain\r\n" +
+            "Content-Range: bytes 20-29/80\r\n" +
+            "\r\n" +
+            DATA.substring(20, 30) + "\r\n";
+        assertResponseContains(section2, response);
+
+        String section3 = boundary + "\r\n" +
+            "Content-Type: text/plain\r\n" +
+            "Content-Range: bytes 40-49/80\r\n" +
+            "\r\n" +
+            DATA.substring(40, 50) + "\r\n";
+        assertResponseContains(section3, response);
+
         assertTrue(body.endsWith(boundary + "--\r\n"));
     }
 

jetty-servlet/src/test/java/org/eclipse/jetty/servlet/DispatcherTest.java

@@ -57,6 +57,7 @@ import org.eclipse.jetty.server.handler.ContextHandler;
 import org.eclipse.jetty.server.handler.ContextHandlerCollection;
 import org.eclipse.jetty.server.handler.ResourceHandler;
 import org.eclipse.jetty.toolchain.test.MavenTestingUtils;
+import org.eclipse.jetty.util.MultiMap;
 import org.eclipse.jetty.util.TypeUtil;
 import org.eclipse.jetty.util.UrlEncoded;
 import org.junit.jupiter.api.AfterEach;
@@ -834,14 +835,14 @@ public class DispatcherTest
             assertEquals(null, request.getPathInfo());
             assertEquals(null, request.getPathTranslated());
 
-            UrlEncoded query = new UrlEncoded();
-            query.decode(request.getQueryString());
+            MultiMap<String> query = new MultiMap<>();
+            UrlEncoded.decodeTo(request.getQueryString(), query, UrlEncoded.ENCODING);
             assertThat(query.getString("do"), is("end"));
 
             // Russian for "selected=Temperature"
-            UrlEncoded q2 = new UrlEncoded();
-            q2.decode(query.getString("else"));
-            String russian = q2.encode();
+            MultiMap<String> q2 = new MultiMap<>();
+            UrlEncoded.decodeTo(query.getString("else"), q2, UrlEncoded.ENCODING);
+            String russian = UrlEncoded.encode(q2, UrlEncoded.ENCODING, false);
             assertThat(russian, is("%D0%B2%D1%8B%D0%B1%D1%80%D0%B0%D0%BD%D0%BE=%D0%A2%D0%B5%D0%BC%D0%BF%D0%B5%D1%80%D0%B0%D1%82%D1%83%D1%80%D0%B0"));
             assertThat(query.containsKey("test"), is(false));
             assertThat(query.containsKey("foreign"), is(false));

jetty-servlet/src/test/java/org/eclipse/jetty/servlet/IncludedServletTest.java

@@ -42,7 +42,6 @@ import org.eclipse.jetty.toolchain.test.IO;
 import org.hamcrest.Matchers;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -108,12 +107,13 @@ public class IncludedServletTest
 
         private void dumpAttrs(String tag, HttpServletRequest req, ServletOutputStream out) throws IOException
         {
-            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_CONTEXT_PATH,
-                req.getAttribute(RequestDispatcher.INCLUDE_CONTEXT_PATH)));
-            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_SERVLET_PATH,
-                req.getAttribute(RequestDispatcher.INCLUDE_SERVLET_PATH)));
-            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_PATH_INFO,
-                req.getAttribute(RequestDispatcher.INCLUDE_PATH_INFO)));
+            String contextPath = (String)req.getAttribute(RequestDispatcher.INCLUDE_CONTEXT_PATH);
+            String servletPath = (String)req.getAttribute(RequestDispatcher.INCLUDE_SERVLET_PATH);
+            String pathInfo = (String)req.getAttribute(RequestDispatcher.INCLUDE_PATH_INFO);
+
+            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_CONTEXT_PATH, contextPath));
+            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_SERVLET_PATH, servletPath));
+            out.println(String.format("%s: %s='%s'", tag, RequestDispatcher.INCLUDE_PATH_INFO, pathInfo));
         }
     }
 
@@ -221,7 +221,6 @@ public class IncludedServletTest
         }
     }
 
-    @Disabled // TODO: complete merge of PR #5058.
     @Test
     public void testIncludeAttributes() throws IOException
     {

jetty-util/src/main/java/org/eclipse/jetty/util/Attachable.java

@@ -0,0 +1,38 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+/**
+ * Abstract mechanism to support attachment of miscellaneous objects.
+ */
+public interface Attachable
+{
+    /**
+     * @return the object attached to this stream
+     * @see #setAttachment(Object)
+     */
+    Object getAttachment();
+
+    /**
+     * Attaches the given object to this stream for later retrieval.
+     *
+     * @param attachment the object to attach to this stream
+     */
+    void setAttachment(Object attachment);
+}

jetty-util/src/main/java/org/eclipse/jetty/util/MultiPartOutputStream.java

@@ -29,8 +29,8 @@ import java.nio.charset.StandardCharsets;
 public class MultiPartOutputStream extends FilterOutputStream
 {
 
-    private static final byte[] __CRLF = {'\r', '\n'};
-    private static final byte[] __DASHDASH = {'-', '-'};
+    private static final byte[] CRLF = {'\r', '\n'};
+    private static final byte[] DASHDASH = {'-', '-'};
 
     public static final String MULTIPART_MIXED = "multipart/mixed";
     public static final String MULTIPART_X_MIXED_REPLACE = "multipart/x-mixed-replace";
@@ -71,11 +71,11 @@ public class MultiPartOutputStream extends FilterOutputStream
         try
         {
             if (inPart)
-                out.write(__CRLF);
-            out.write(__DASHDASH);
+                out.write(CRLF);
+            out.write(DASHDASH);
             out.write(boundaryBytes);
-            out.write(__DASHDASH);
-            out.write(__CRLF);
+            out.write(DASHDASH);
+            out.write(CRLF);
             inPart = false;
         }
         finally
@@ -104,15 +104,19 @@ public class MultiPartOutputStream extends FilterOutputStream
         throws IOException
     {
         if (inPart)
-            out.write(__CRLF);
+        {
+            out.write(CRLF);
+        }
         inPart = true;
-        out.write(__DASHDASH);
+        out.write(DASHDASH);
         out.write(boundaryBytes);
-        out.write(__CRLF);
+        out.write(CRLF);
         if (contentType != null)
+        {
             out.write(("Content-Type: " + contentType).getBytes(StandardCharsets.ISO_8859_1));
-        out.write(__CRLF);
-        out.write(__CRLF);
+            out.write(CRLF);
+        }
+        out.write(CRLF);
     }
 
     /**
@@ -126,20 +130,22 @@ public class MultiPartOutputStream extends FilterOutputStream
         throws IOException
     {
         if (inPart)
-            out.write(__CRLF);
+            out.write(CRLF);
         inPart = true;
-        out.write(__DASHDASH);
+        out.write(DASHDASH);
         out.write(boundaryBytes);
-        out.write(__CRLF);
+        out.write(CRLF);
         if (contentType != null)
+        {
             out.write(("Content-Type: " + contentType).getBytes(StandardCharsets.ISO_8859_1));
-        out.write(__CRLF);
+            out.write(CRLF);
+        }
         for (int i = 0; headers != null && i < headers.length; i++)
         {
             out.write(headers[i].getBytes(StandardCharsets.ISO_8859_1));
-            out.write(__CRLF);
+            out.write(CRLF);
         }
-        out.write(__CRLF);
+        out.write(CRLF);
     }
 
     @Override
@@ -148,7 +154,3 @@ public class MultiPartOutputStream extends FilterOutputStream
         out.write(b, off, len);
     }
 }
-
-
-
-

jetty-util/src/main/java/org/eclipse/jetty/util/Pool.java

@@ -0,0 +1,446 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import org.eclipse.jetty.util.component.Dumpable;
+import org.eclipse.jetty.util.thread.AutoLock;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A fast container of poolable objects, with optional support for
+ * multiplexing, max usage count and thread-local caching.
+ * <p>
+ * The thread-local caching mechanism is about remembering up to N previously
+ * used entries into a thread-local single-threaded collection.
+ * When that collection is not empty, its entries are removed one by one
+ * during acquisition until an entry that can be acquired is found.
+ * This can greatly speed up acquisition when both the acquisition and the
+ * release of the entries is done on the same thread as this avoids iterating
+ * the global, thread-safe collection of entries.
+ * @param <T>
+ */
+public class Pool<T> implements AutoCloseable, Dumpable
+{
+    private static final Logger LOGGER = LoggerFactory.getLogger(Pool.class);
+
+    private final List<Entry> sharedList = new CopyOnWriteArrayList<>();
+    /*
+     * The cache is used to avoid hammering on the first index of the entry list.
+     * Caches can become poisoned (i.e.: containing entries that are in use) when
+     * the release isn't done by the acquiring thread or when the entry pool is
+     * undersized compared to the load applied on it.
+     * When an entry can't be found in the cache, the global list is iterated
+     * normally so the cache has no visible effect besides performance.
+     */
+    private final ThreadLocal<List<Entry>> cache;
+    private final AutoLock lock = new AutoLock();
+    private final int maxEntries;
+    private final int cacheSize;
+    private volatile boolean closed;
+    private volatile int maxMultiplex = 1;
+    private volatile int maxUsageCount = -1;
+
+    /**
+     * Construct a Pool with the specified thread-local cache size.
+     *
+     * @param maxEntries the maximum amount of entries that the pool will accept.
+     * @param cacheSize the thread-local cache size. A value less than 1 means the cache is disabled.
+     */
+    public Pool(int maxEntries, int cacheSize)
+    {
+        this.maxEntries = maxEntries;
+        this.cacheSize = cacheSize;
+        if (cacheSize > 0)
+            this.cache = ThreadLocal.withInitial(() -> new ArrayList<Entry>(cacheSize));
+        else
+            this.cache = null;
+    }
+
+    public int getPendingConnectionCount()
+    {
+        return (int)sharedList.stream().filter(entry -> entry.getPooled() == null).count();
+    }
+
+    public int getIdleConnectionCount()
+    {
+        return (int)sharedList.stream().filter(Entry::isIdle).count();
+    }
+
+    public int getInUseConnectionCount()
+    {
+        return (int)sharedList.stream().filter(entry -> !entry.isIdle()).count();
+    }
+
+    public int getMaxEntries()
+    {
+        return maxEntries;
+    }
+
+    public int getMaxMultiplex()
+    {
+        return maxMultiplex;
+    }
+
+    public final void setMaxMultiplex(int maxMultiplex)
+    {
+        if (maxMultiplex < 1)
+            throw new IllegalArgumentException("Max multiplex must be >= 1");
+        this.maxMultiplex = maxMultiplex;
+    }
+
+    public int getMaxUsageCount()
+    {
+        return maxUsageCount;
+    }
+
+    public final void setMaxUsageCount(int maxUsageCount)
+    {
+        if (maxUsageCount == 0)
+            throw new IllegalArgumentException("Max usage count must be != 0");
+        this.maxUsageCount = maxUsageCount;
+    }
+
+    /**
+     * Create a new disabled slot into the pool. The returned entry
+     * won't be acquirable as long as {@link Entry#enable(Object)}
+     * has not been called.
+     *
+     * @param maxReservations the max desired number of reserved entries,
+     * or a negative number to always trigger the reservation of a new entry.
+     * @return a disabled entry that is contained in the pool,
+     * or null if the pool is closed or if the pool already contains
+     * {@link #getMaxEntries()} entries.
+     */
+    public Entry reserve(int maxReservations)
+    {
+        if (maxReservations >= 0 && getPendingConnectionCount() >= maxReservations)
+            return null;
+
+        try (AutoLock l = lock.lock())
+        {
+            if (!closed && sharedList.size() < maxEntries)
+            {
+                Entry entry = new Entry();
+                sharedList.add(entry);
+                return entry;
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Acquire the entry from the pool at the specified index. This method bypasses the thread-local mechanism.
+     *
+     * @param idx the index of the entry to acquire.
+     * @return the specified entry or null if there is none at the specified index or if it is not available.
+     */
+    public Entry acquireAt(int idx)
+    {
+        if (closed)
+            return null;
+
+        try
+        {
+            Entry entry = sharedList.get(idx);
+            if (entry.tryAcquire())
+                return entry;
+        }
+        catch (IndexOutOfBoundsException e)
+        {
+            // no entry at that index
+        }
+        return null;
+    }
+
+    /**
+     * Acquire an entry from the pool.
+     *
+     * @return an entry from the pool or null if none is available.
+     */
+    public Entry acquire()
+    {
+        if (closed)
+            return null;
+
+        // first check the thread-local cache
+        if (cache != null)
+        {
+            List<Entry> cachedList = cache.get();
+            while (!cachedList.isEmpty())
+            {
+                Entry cachedEntry = cachedList.remove(cachedList.size() - 1);
+                if (cachedEntry.tryAcquire())
+                    return cachedEntry;
+            }
+        }
+
+        // then iterate the shared list
+        for (Entry entry : sharedList)
+        {
+            if (entry.tryAcquire())
+                return entry;
+        }
+        return null;
+    }
+
+    /**
+     * This method will return an acquired object to the pool. Objects
+     * that are acquired from the pool but never released will result
+     * in a memory leak.
+     *
+     * @param entry the value to return to the pool
+     * @return true if the entry was released and could be acquired again,
+     * false if the entry should be removed by calling {@link #remove(Pool.Entry)}
+     * and the object contained by the entry should be disposed.
+     * @throws NullPointerException if value is null
+     */
+    public boolean release(Entry entry)
+    {
+        if (closed)
+            return false;
+
+        // first mark it as unused
+        boolean reusable = entry.tryRelease();
+
+        // then cache the released entry
+        if (cache != null && reusable)
+        {
+            List<Entry> cachedList = cache.get();
+            if (cachedList.size() < cacheSize)
+                cachedList.add(entry);
+        }
+        return reusable;
+    }
+
+    /**
+     * Remove a value from the pool.
+     *
+     * @param entry the value to remove
+     * @return true if the entry was removed, false otherwise
+     */
+    public boolean remove(Entry entry)
+    {
+        if (closed)
+            return false;
+
+        if (!entry.tryRemove())
+        {
+            if (LOGGER.isDebugEnabled())
+                LOGGER.debug("Attempt to remove an object from the pool that is still in use: {}", entry);
+            return false;
+        }
+
+        boolean removed = sharedList.remove(entry);
+        if (!removed)
+        {
+            if (LOGGER.isDebugEnabled())
+                LOGGER.debug("Attempt to remove an object from the pool that does not exist: {}", entry);
+        }
+
+        return removed;
+    }
+
+    public boolean isClosed()
+    {
+        return closed;
+    }
+
+    @Override
+    public void close()
+    {
+        List<Entry> copy;
+        try (AutoLock l = lock.lock())
+        {
+            closed = true;
+            copy = new ArrayList<>(sharedList);
+            sharedList.clear();
+        }
+
+        // iterate the copy and close its entries
+        for (Entry entry : copy)
+        {
+            if (entry.tryRemove() && entry.pooled instanceof Closeable)
+            {
+                try
+                {
+                    ((Closeable)entry.pooled).close();
+                }
+                catch (IOException e)
+                {
+                    LOGGER.warn("Error closing entry {}", entry, e);
+                }
+            }
+        }
+    }
+
+    public int size()
+    {
+        return sharedList.size();
+    }
+
+    public Collection<Entry> values()
+    {
+        return Collections.unmodifiableCollection(sharedList);
+    }
+
+    @Override
+    public void dump(Appendable out, String indent) throws IOException
+    {
+        Dumpable.dumpObjects(out, indent, this);
+    }
+
+    @Override
+    public String toString()
+    {
+        return getClass().getSimpleName() + " size=" + sharedList.size() + " closed=" + closed + " entries=" + sharedList;
+    }
+
+    public class Entry
+    {
+        // hi: positive=open/maxUsage counter,negative=closed lo: multiplexing counter
+        private final AtomicBiInteger state;
+        private volatile T pooled;
+
+        public Entry()
+        {
+            this.state = new AtomicBiInteger(-1, 0);
+        }
+
+        public T getPooled()
+        {
+            return pooled;
+        }
+
+        public void enable(T pooled)
+        {
+            if (!isClosed())
+                throw new IllegalStateException("Open entries cannot be enabled : " + this);
+            Objects.requireNonNull(pooled);
+            this.pooled = pooled;
+            state.set(0, 0);
+        }
+
+        /**
+         * Try to acquire the entry if possible by incrementing both the usage
+         * count and the multiplex count.
+         * @return true if the usage count is &lt;= maxUsageCount and
+         * the multiplex count is maxMultiplex and the entry is not closed,
+         * false otherwise.
+         */
+        public boolean tryAcquire()
+        {
+            while (true)
+            {
+                long encoded = state.get();
+                int usageCount = AtomicBiInteger.getHi(encoded);
+                boolean closed = usageCount < 0;
+                int multiplexingCount = AtomicBiInteger.getLo(encoded);
+                int currentMaxUsageCount = maxUsageCount;
+                if (closed || multiplexingCount >= maxMultiplex || (currentMaxUsageCount > 0 && usageCount >= currentMaxUsageCount))
+                    return false;
+
+                if (state.compareAndSet(encoded, usageCount + 1, multiplexingCount + 1))
+                    return true;
+            }
+        }
+
+        /**
+         * Try to release the entry if possible by decrementing the multiplexing
+         * count unless the entity is closed.
+         * @return true if the entry was released,
+         * false if {@link #tryRemove()} should be called.
+         */
+        public boolean tryRelease()
+        {
+            int newMultiplexingCount;
+            int usageCount;
+            while (true)
+            {
+                long encoded = state.get();
+                usageCount = AtomicBiInteger.getHi(encoded);
+                boolean closed = usageCount < 0;
+                if (closed)
+                    return false;
+
+                newMultiplexingCount = AtomicBiInteger.getLo(encoded) - 1;
+                if (newMultiplexingCount < 0)
+                    throw new IllegalStateException("Cannot release an already released entry");
+
+                if (state.compareAndSet(encoded, usageCount, newMultiplexingCount))
+                    break;
+            }
+
+            int currentMaxUsageCount = maxUsageCount;
+            boolean overUsed = currentMaxUsageCount > 0 && usageCount >= currentMaxUsageCount;
+            return !(overUsed && newMultiplexingCount == 0);
+        }
+
+        /**
+         * Try to mark the entry as removed.
+         * @return true if the entry has to be removed from the containing pool, false otherwise.
+         */
+        public boolean tryRemove()
+        {
+            while (true)
+            {
+                long encoded = state.get();
+                int usageCount = AtomicBiInteger.getHi(encoded);
+                int multiplexCount = AtomicBiInteger.getLo(encoded);
+                int newMultiplexCount = Math.max(multiplexCount - 1, 0);
+
+                boolean removed = state.compareAndSet(usageCount, -1, multiplexCount, newMultiplexCount);
+                if (removed)
+                    return newMultiplexCount == 0;
+            }
+        }
+
+        public boolean isClosed()
+        {
+            return state.getHi() < 0;
+        }
+
+        public boolean isIdle()
+        {
+            return state.getLo() <= 0;
+        }
+
+        public int getUsageCount()
+        {
+            return Math.max(state.getHi(), 0);
+        }
+
+        @Override
+        public String toString()
+        {
+            long encoded = state.get();
+            return super.toString() + " stateHi=" + AtomicBiInteger.getHi(encoded) +
+                " stateLo=" + AtomicBiInteger.getLo(encoded) + " pooled=" + pooled;
+        }
+    }
+}

jetty-util/src/main/java/org/eclipse/jetty/util/UrlEncoded.java

@@ -44,19 +44,11 @@ import static org.eclipse.jetty.util.TypeUtil.convertHexDigit;
  * passing a parameter or setting the "org.eclipse.jetty.util.UrlEncoding.charset"
  * System property.
  * </p>
- * <p>
- * The hashtable either contains String single values, vectors
- * of String or arrays of Strings.
- * </p>
- * <p>
- * This class is only partially synchronised.  In particular, simple
- * get operations are not protected from concurrent updates.
- * </p>
  *
  * @see java.net.URLEncoder
  */
 @SuppressWarnings("serial")
-public class UrlEncoded extends MultiMap<String> implements Cloneable
+public class UrlEncoded
 {
     static final Logger LOG = LoggerFactory.getLogger(UrlEncoded.class);
 
@@ -87,62 +79,8 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
         ENCODING = encoding;
     }
 
-    public UrlEncoded(UrlEncoded url)
+    private UrlEncoded()
     {
-        super(url);
-    }
-
-    public UrlEncoded()
-    {
-    }
-
-    public UrlEncoded(String query)
-    {
-        decodeTo(query, this, ENCODING);
-    }
-
-    public void decode(String query)
-    {
-        decodeTo(query, this, ENCODING);
-    }
-
-    public void decode(String query, Charset charset)
-    {
-        decodeTo(query, this, charset);
-    }
-
-    /**
-     * Encode MultiMap with % encoding for UTF8 sequences.
-     *
-     * @return the MultiMap as a string with % encoding
-     */
-    public String encode()
-    {
-        return encode(ENCODING, false);
-    }
-
-    /**
-     * Encode MultiMap with % encoding for arbitrary Charset sequences.
-     *
-     * @param charset the charset to use for encoding
-     * @return the MultiMap as a string encoded with % encodings
-     */
-    public String encode(Charset charset)
-    {
-        return encode(charset, false);
-    }
-
-    /**
-     * Encode MultiMap with % encoding.
-     *
-     * @param charset the charset to encode with
-     * @param equalsForNullValue if True, then an '=' is always used, even
-     * for parameters without a value. e.g. <code>"blah?a=&amp;b=&amp;c="</code>.
-     * @return the MultiMap as a string encoded with % encodings
-     */
-    public synchronized String encode(Charset charset, boolean equalsForNullValue)
-    {
-        return encode(this, charset, equalsForNullValue);
     }
 
     /**
@@ -190,11 +128,10 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
 
                     if (val != null)
                     {
-                        String str = val;
-                        if (str.length() > 0)
+                        if (val.length() > 0)
                         {
                             result.append('=');
-                            result.append(encodeString(str, charset));
+                            result.append(encodeString(val, charset));
                         }
                         else if (equalsForNullValue)
                             result.append('=');
@@ -228,6 +165,18 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
      * @param charset the charset to use for decoding
      */
     public static void decodeTo(String content, MultiMap<String> map, Charset charset)
+    {
+        decodeTo(content, map, charset, -1);
+    }
+
+    /**
+     * Decoded parameters to Map.
+     *
+     * @param content the string containing the encoded parameters
+     * @param map the MultiMap to put parsed query parameters into
+     * @param charset the charset to use for decoding
+     */
+    public static void decodeTo(String content, MultiMap<String> map, Charset charset, int maxKeys)
     {
         if (charset == null)
             charset = ENCODING;
@@ -238,64 +187,62 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
             return;
         }
 
-        synchronized (map)
+        String key = null;
+        String value;
+        int mark = -1;
+        boolean encoded = false;
+        for (int i = 0; i < content.length(); i++)
         {
-            String key = null;
-            String value;
-            int mark = -1;
-            boolean encoded = false;
-            for (int i = 0; i < content.length(); i++)
+            char c = content.charAt(i);
+            switch (c)
             {
-                char c = content.charAt(i);
-                switch (c)
-                {
-                    case '&':
-                        int l = i - mark - 1;
-                        value = l == 0 ? "" : (encoded ? decodeString(content, mark + 1, l, charset) : content.substring(mark + 1, i));
-                        mark = i;
-                        encoded = false;
-                        if (key != null)
-                        {
-                            map.add(key, value);
-                        }
-                        else if (value != null && value.length() > 0)
-                        {
-                            map.add(value, "");
-                        }
-                        key = null;
-                        value = null;
+                case '&':
+                    int l = i - mark - 1;
+                    value = l == 0 ? "" : (encoded ? decodeString(content, mark + 1, l, charset) : content.substring(mark + 1, i));
+                    mark = i;
+                    encoded = false;
+                    if (key != null)
+                    {
+                        map.add(key, value);
+                    }
+                    else if (value != null && value.length() > 0)
+                    {
+                        map.add(value, "");
+                    }
+                    checkMaxKeys(map, maxKeys);
+                    key = null;
+                    value = null;
+                    break;
+                case '=':
+                    if (key != null)
                         break;
-                    case '=':
-                        if (key != null)
-                            break;
-                        key = encoded ? decodeString(content, mark + 1, i - mark - 1, charset) : content.substring(mark + 1, i);
-                        mark = i;
-                        encoded = false;
-                        break;
-                    case '+':
-                        encoded = true;
-                        break;
-                    case '%':
-                        encoded = true;
-                        break;
-                }
+                    key = encoded ? decodeString(content, mark + 1, i - mark - 1, charset) : content.substring(mark + 1, i);
+                    mark = i;
+                    encoded = false;
+                    break;
+                case '+':
+                case '%':
+                    encoded = true;
+                    break;
             }
+        }
 
-            if (key != null)
+        if (key != null)
+        {
+            int l = content.length() - mark - 1;
+            value = l == 0 ? "" : (encoded ? decodeString(content, mark + 1, l, charset) : content.substring(mark + 1));
+            map.add(key, value);
+            checkMaxKeys(map, maxKeys);
+        }
+        else if (mark < content.length())
+        {
+            key = encoded
+                ? decodeString(content, mark + 1, content.length() - mark - 1, charset)
+                : content.substring(mark + 1);
+            if (key != null && key.length() > 0)
             {
-                int l = content.length() - mark - 1;
-                value = l == 0 ? "" : (encoded ? decodeString(content, mark + 1, l, charset) : content.substring(mark + 1));
-                map.add(key, value);
-            }
-            else if (mark < content.length())
-            {
-                key = encoded
-                    ? decodeString(content, mark + 1, content.length() - mark - 1, charset)
-                    : content.substring(mark + 1);
-                if (key != null && key.length() > 0)
-                {
-                    map.add(key, "");
-                }
+                map.add(key, "");
+                checkMaxKeys(map, maxKeys);
             }
         }
     }
@@ -316,76 +263,73 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
     public static void decodeUtf8To(String query, int offset, int length, MultiMap<String> map)
     {
         Utf8StringBuilder buffer = new Utf8StringBuilder();
-        synchronized (map)
+        String key = null;
+        String value;
+
+        int end = offset + length;
+        for (int i = offset; i < end; i++)
         {
-            String key = null;
-            String value = null;
-
-            int end = offset + length;
-            for (int i = offset; i < end; i++)
+            char c = query.charAt(i);
+            switch (c)
             {
-                char c = query.charAt(i);
-                switch (c)
-                {
-                    case '&':
-                        value = buffer.toReplacedString();
-                        buffer.reset();
-                        if (key != null)
-                        {
-                            map.add(key, value);
-                        }
-                        else if (value != null && value.length() > 0)
-                        {
-                            map.add(value, "");
-                        }
-                        key = null;
-                        value = null;
-                        break;
+                case '&':
+                    value = buffer.toReplacedString();
+                    buffer.reset();
+                    if (key != null)
+                    {
+                        map.add(key, value);
+                    }
+                    else if (value != null && value.length() > 0)
+                    {
+                        map.add(value, "");
+                    }
+                    key = null;
+                    break;
 
-                    case '=':
-                        if (key != null)
-                        {
-                            buffer.append(c);
-                            break;
-                        }
-                        key = buffer.toReplacedString();
-                        buffer.reset();
-                        break;
-
-                    case '+':
-                        buffer.append((byte)' ');
-                        break;
-
-                    case '%':
-                        if (i + 2 < end)
-                        {
-                            char hi = query.charAt(++i);
-                            char lo = query.charAt(++i);
-                            buffer.append(decodeHexByte(hi, lo));
-                        }
-                        else
-                        {
-                            throw new Utf8Appendable.NotUtf8Exception("Incomplete % encoding");
-                        }
-                        break;
-
-                    default:
+                case '=':
+                    if (key != null)
+                    {
                         buffer.append(c);
                         break;
-                }
-            }
+                    }
+                    key = buffer.toReplacedString();
+                    buffer.reset();
+                    break;
 
-            if (key != null)
-            {
-                value = buffer.toReplacedString();
-                buffer.reset();
-                map.add(key, value);
-            }
-            else if (buffer.length() > 0)
-            {
-                map.add(buffer.toReplacedString(), "");
+                case '+':
+                    buffer.append((byte)' ');
+                    break;
+
+                case '%':
+                    if (i + 2 < end)
+                    {
+                        char hi = query.charAt(++i);
+                        char lo = query.charAt(++i);
+                        buffer.append(decodeHexByte(hi, lo));
+                    }
+                    else
+                    {
+                        throw new Utf8Appendable.NotUtf8Exception("Incomplete % encoding");
+                    }
+                    break;
+
+                default:
+                    buffer.append(c);
+                    break;
             }
         }
+
+        if (key != null)
+        {
+            value = buffer.toReplacedString();
+            buffer.reset();
+            map.add(key, value);
+        }
+        else if (buffer.length() > 0)
+        {
+            map.add(buffer.toReplacedString(), "");
+        }
+
     }
 
     /**
@@ -400,74 +344,70 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
     public static void decode88591To(InputStream in, MultiMap<String> map, int maxLength, int maxKeys)
         throws IOException
     {
-        synchronized (map)
+        StringBuilder buffer = new StringBuilder();
+        String key = null;
+        String value;
+
+        int b;
+
+        int totalLength = 0;
+        while ((b = in.read()) >= 0)
         {
-            StringBuilder buffer = new StringBuilder();
-            String key = null;
-            String value = null;
-
-            int b;
-
-            int totalLength = 0;
-            while ((b = in.read()) >= 0)
+            switch ((char)b)
             {
-                switch ((char)b)
-                {
-                    case '&':
-                        value = buffer.length() == 0 ? "" : buffer.toString();
-                        buffer.setLength(0);
-                        if (key != null)
-                        {
-                            map.add(key, value);
-                        }
-                        else if (value.length() > 0)
-                        {
-                            map.add(value, "");
-                        }
-                        key = null;
-                        value = null;
-                        checkMaxKeys(map, maxKeys);
-                        break;
+                case '&':
+                    value = buffer.length() == 0 ? "" : buffer.toString();
+                    buffer.setLength(0);
+                    if (key != null)
+                    {
+                        map.add(key, value);
+                    }
+                    else if (value.length() > 0)
+                    {
+                        map.add(value, "");
+                    }
+                    key = null;
+                    checkMaxKeys(map, maxKeys);
+                    break;
 
-                    case '=':
-                        if (key != null)
-                        {
-                            buffer.append((char)b);
-                            break;
-                        }
-                        key = buffer.toString();
-                        buffer.setLength(0);
-                        break;
-
-                    case '+':
-                        buffer.append(' ');
-                        break;
-
-                    case '%':
-                        int code0 = in.read();
-                        int code1 = in.read();
-                        buffer.append(decodeHexChar(code0, code1));
-                        break;
-
-                    default:
+                case '=':
+                    if (key != null)
+                    {
                         buffer.append((char)b);
                         break;
-                }
-                checkMaxLength(++totalLength, maxLength);
-            }
+                    }
+                    key = buffer.toString();
+                    buffer.setLength(0);
+                    break;
 
-            if (key != null)
-            {
-                value = buffer.length() == 0 ? "" : buffer.toString();
-                buffer.setLength(0);
-                map.add(key, value);
+                case '+':
+                    buffer.append(' ');
+                    break;
+
+                case '%':
+                    int code0 = in.read();
+                    int code1 = in.read();
+                    buffer.append(decodeHexChar(code0, code1));
+                    break;
+
+                default:
+                    buffer.append((char)b);
+                    break;
             }
-            else if (buffer.length() > 0)
-            {
-                map.add(buffer.toString(), "");
-            }
-            checkMaxKeys(map, maxKeys);
+            checkMaxLength(++totalLength, maxLength);
         }
+
+        if (key != null)
+        {
+            value = buffer.length() == 0 ? "" : buffer.toString();
+            buffer.setLength(0);
+            map.add(key, value);
+        }
+        else if (buffer.length() > 0)
+        {
+            map.add(buffer.toString(), "");
+        }
+        checkMaxKeys(map, maxKeys);
     }
 
     /**
@@ -482,74 +422,70 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
     public static void decodeUtf8To(InputStream in, MultiMap<String> map, int maxLength, int maxKeys)
         throws IOException
     {
-        synchronized (map)
+        Utf8StringBuilder buffer = new Utf8StringBuilder();
+        String key = null;
+        String value;
+
+        int b;
+
+        int totalLength = 0;
+        while ((b = in.read()) >= 0)
         {
-            Utf8StringBuilder buffer = new Utf8StringBuilder();
-            String key = null;
-            String value = null;
-
-            int b;
-
-            int totalLength = 0;
-            while ((b = in.read()) >= 0)
+            switch ((char)b)
             {
-                switch ((char)b)
-                {
-                    case '&':
-                        value = buffer.toReplacedString();
-                        buffer.reset();
-                        if (key != null)
-                        {
-                            map.add(key, value);
-                        }
-                        else if (value != null && value.length() > 0)
-                        {
-                            map.add(value, "");
-                        }
-                        key = null;
-                        value = null;
-                        checkMaxKeys(map, maxKeys);
-                        break;
+                case '&':
+                    value = buffer.toReplacedString();
+                    buffer.reset();
+                    if (key != null)
+                    {
+                        map.add(key, value);
+                    }
+                    else if (value != null && value.length() > 0)
+                    {
+                        map.add(value, "");
+                    }
+                    key = null;
+                    checkMaxKeys(map, maxKeys);
+                    break;
 
-                    case '=':
-                        if (key != null)
-                        {
-                            buffer.append((byte)b);
-                            break;
-                        }
-                        key = buffer.toReplacedString();
-                        buffer.reset();
-                        break;
-
-                    case '+':
-                        buffer.append((byte)' ');
-                        break;
-
-                    case '%':
-                        char code0 = (char)in.read();
-                        char code1 = (char)in.read();
-                        buffer.append(decodeHexByte(code0, code1));
-                        break;
-
-                    default:
+                case '=':
+                    if (key != null)
+                    {
                         buffer.append((byte)b);
                         break;
-                }
-                checkMaxLength(++totalLength, maxLength);
-            }
+                    }
+                    key = buffer.toReplacedString();
+                    buffer.reset();
+                    break;
 
-            if (key != null)
-            {
-                value = buffer.toReplacedString();
-                buffer.reset();
-                map.add(key, value);
+                case '+':
+                    buffer.append((byte)' ');
+                    break;
+
+                case '%':
+                    char code0 = (char)in.read();
+                    char code1 = (char)in.read();
+                    buffer.append(decodeHexByte(code0, code1));
+                    break;
+
+                default:
+                    buffer.append((byte)b);
+                    break;
             }
-            else if (buffer.length() > 0)
-            {
-                map.add(buffer.toReplacedString(), "");
-            }
-            checkMaxKeys(map, maxKeys);
+            checkMaxLength(++totalLength, maxLength);
         }
+
+        if (key != null)
+        {
+            value = buffer.toReplacedString();
+            buffer.reset();
+            map.add(key, value);
+        }
+        else if (buffer.length() > 0)
+        {
+            map.add(buffer.toReplacedString(), "");
+        }
+        checkMaxKeys(map, maxKeys);
     }
 
     public static void decodeUtf16To(InputStream in, MultiMap<String> map, int maxLength, int maxKeys) throws IOException
@@ -558,8 +494,7 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
         StringWriter buf = new StringWriter(8192);
         IO.copy(input, buf, maxLength);
 
-        // TODO implement maxKeys
-        decodeTo(buf.getBuffer().toString(), map, StandardCharsets.UTF_16);
+        decodeTo(buf.getBuffer().toString(), map, StandardCharsets.UTF_16, maxKeys);
     }
 
     /**
@@ -627,77 +562,73 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
             return;
         }
 
-        synchronized (map)
+        String key = null;
+        String value;
+
+        int c;
+
+        int totalLength = 0;
+
+        try (ByteArrayOutputStream2 output = new ByteArrayOutputStream2())
         {
-            String key = null;
-            String value = null;
+            int size;
 
-            int c;
-
-            int totalLength = 0;
-
-            try (ByteArrayOutputStream2 output = new ByteArrayOutputStream2())
+            while ((c = in.read()) > 0)
             {
-                int size = 0;
-
-                while ((c = in.read()) > 0)
+                switch ((char)c)
                 {
-                    switch ((char)c)
-                    {
-                        case '&':
-                            size = output.size();
-                            value = size == 0 ? "" : output.toString(charset);
-                            output.setCount(0);
-                            if (key != null)
-                            {
-                                map.add(key, value);
-                            }
-                            else if (value != null && value.length() > 0)
-                            {
-                                map.add(value, "");
-                            }
-                            key = null;
-                            value = null;
-                            checkMaxKeys(map, maxKeys);
-                            break;
-                        case '=':
-                            if (key != null)
-                            {
-                                output.write(c);
-                                break;
-                            }
-                            size = output.size();
-                            key = size == 0 ? "" : output.toString(charset);
-                            output.setCount(0);
-                            break;
-                        case '+':
-                            output.write(' ');
-                            break;
-                        case '%':
-                            int code0 = in.read();
-                            int code1 = in.read();
-                            output.write(decodeHexChar(code0, code1));
-                            break;
-                        default:
+                    case '&':
+                        size = output.size();
+                        value = size == 0 ? "" : output.toString(charset);
+                        output.setCount(0);
+                        if (key != null)
+                        {
+                            map.add(key, value);
+                        }
+                        else if (value != null && value.length() > 0)
+                        {
+                            map.add(value, "");
+                        }
+                        key = null;
+                        checkMaxKeys(map, maxKeys);
+                        break;
+                    case '=':
+                        if (key != null)
+                        {
                             output.write(c);
                             break;
-                    }
-                    checkMaxLength(++totalLength, maxLength);
+                        }
+                        size = output.size();
+                        key = size == 0 ? "" : output.toString(charset);
+                        output.setCount(0);
+                        break;
+                    case '+':
+                        output.write(' ');
+                        break;
+                    case '%':
+                        int code0 = in.read();
+                        int code1 = in.read();
+                        output.write(decodeHexChar(code0, code1));
+                        break;
+                    default:
+                        output.write(c);
+                        break;
                 }
-
-                size = output.size();
-                if (key != null)
-                {
-                    value = size == 0 ? "" : output.toString(charset);
-                    output.setCount(0);
-                    map.add(key, value);
-                }
-                else if (size > 0)
-                {
-                    map.add(output.toString(charset), "");
-                }
-                checkMaxKeys(map, maxKeys);
+                checkMaxLength(++totalLength, maxLength);
             }
+
+            size = output.size();
+            if (key != null)
+            {
+                value = size == 0 ? "" : output.toString(charset);
+                output.setCount(0);
+                map.add(key, value);
+            }
+            else if (size > 0)
+            {
+                map.add(output.toString(charset), "");
+            }
+            checkMaxKeys(map, maxKeys);
         }
     }
 
@@ -747,7 +678,7 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
             for (int i = 0; i < length; i++)
             {
                 char c = encoded.charAt(offset + i);
-                if (c < 0 || c > 0xff)
+                if (c > 0xff)
                 {
                     if (buffer == null)
                     {
@@ -808,7 +739,7 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
             for (int i = 0; i < length; i++)
             {
                 char c = encoded.charAt(offset + i);
-                if (c < 0 || c > 0xff)
+                if (c > 0xff)
                 {
                     if (buffer == null)
                     {
@@ -838,7 +769,7 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
 
                     byte[] ba = new byte[length];
                     int n = 0;
-                    while (c >= 0 && c <= 0xff)
+                    while (c <= 0xff)
                     {
                         if (c == '%')
                         {
@@ -935,18 +866,15 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
     {
         if (charset == null)
             charset = ENCODING;
-        byte[] bytes = null;
+        byte[] bytes;
         bytes = string.getBytes(charset);
 
-        int len = bytes.length;
         byte[] encoded = new byte[bytes.length * 3];
         int n = 0;
         boolean noEncode = true;
 
-        for (int i = 0; i < len; i++)
+        for (byte b : bytes)
         {
-            byte b = bytes[i];
-
             if (b == ' ')
             {
                 noEncode = false;
@@ -981,10 +909,4 @@ public class UrlEncoded extends MultiMap<String> implements Cloneable
 
         return new String(encoded, 0, n, charset);
     }
-
-    @Override
-    public Object clone()
-    {
-        return new UrlEncoded(this);
-    }
 }

jetty-util/src/main/java/org/eclipse/jetty/util/component/Graceful.java

@@ -139,4 +139,54 @@ public interface Graceful
 
         return CompletableFuture.allOf(gracefuls.stream().map(Graceful::shutdown).toArray(CompletableFuture[]::new));
     }
+
+    /**
+     * Utility method to execute a {@link ThrowingRunnable} in a new daemon thread and
+     * be notified of the result in a {@link CompletableFuture}.
+     * @param runnable the ThrowingRunnable to run.
+     * @return the CompletableFuture to be notified when the runnable either completes or fails.
+     */
+    static CompletableFuture<Void> shutdown(ThrowingRunnable runnable)
+    {
+        AtomicReference<Thread> stopThreadReference = new AtomicReference<>();
+        CompletableFuture<Void> shutdown = new CompletableFuture<>()
+        {
+            @Override
+            public boolean cancel(boolean mayInterruptIfRunning)
+            {
+                boolean canceled = super.cancel(mayInterruptIfRunning);
+                if (canceled && mayInterruptIfRunning)
+                {
+                    Thread thread = stopThreadReference.get();
+                    if (thread != null)
+                        thread.interrupt();
+                }
+
+                return canceled;
+            }
+        };
+
+        Thread stopThread = new Thread(() ->
+        {
+            try
+            {
+                runnable.run();
+                shutdown.complete(null);
+            }
+            catch (Throwable t)
+            {
+                shutdown.completeExceptionally(t);
+            }
+        });
+        stopThread.setDaemon(true);
+        stopThreadReference.set(stopThread);
+        stopThread.start();
+        return shutdown;
+    }
+
+    @FunctionalInterface
+    interface ThrowingRunnable
+    {
+        void run() throws Exception;
+    }
 }

jetty-util/src/main/java/org/eclipse/jetty/util/ssl/KeyStoreScanner.java

@@ -27,8 +27,8 @@ import org.eclipse.jetty.util.Scanner;
 import org.eclipse.jetty.util.annotation.ManagedAttribute;
 import org.eclipse.jetty.util.annotation.ManagedOperation;
 import org.eclipse.jetty.util.component.ContainerLifeCycle;
-import org.eclipse.jetty.util.log.Log;
-import org.eclipse.jetty.util.log.Logger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * <p>The {@link KeyStoreScanner} is used to monitor the KeyStore file used by the {@link SslContextFactory}.
@@ -38,7 +38,7 @@ import org.eclipse.jetty.util.log.Logger;
  */
 public class KeyStoreScanner extends ContainerLifeCycle implements Scanner.DiscreteListener
 {
-    private static final Logger LOG = Log.getLogger(KeyStoreScanner.class);
+    private static final Logger LOG = LoggerFactory.getLogger(KeyStoreScanner.class);
 
     private final SslContextFactory sslContextFactory;
     private final File keystoreFile;

jetty-util/src/test/java/org/eclipse/jetty/util/PoolTest.java

@@ -0,0 +1,442 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.io.Closeable;
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.junit.jupiter.api.Test;
+
+import static java.util.stream.Collectors.toList;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.nullValue;
+import static org.hamcrest.Matchers.sameInstance;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class PoolTest
+{
+
+    @Test
+    public void testAcquireRelease()
+    {
+        Pool<String> pool = new Pool<>(1,0);
+        pool.reserve(-1).enable("aaa");
+
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(true));
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(e1.getPooled(), equalTo("aaa"));
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(false));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(pool.release(e1), is(true));
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(true));
+        assertThrows(IllegalStateException.class, () -> pool.release(e1));
+        Pool<String>.Entry e2 = pool.acquire();
+        assertThat(e2.getPooled(), equalTo("aaa"));
+        assertThat(pool.release(e2), is(true));
+        assertThrows(NullPointerException.class, () -> pool.release(null));
+    }
+
+    @Test
+    public void testRemoveBeforeRelease()
+    {
+        Pool<String> pool = new Pool<>(1,0);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.remove(e1), is(true));
+        assertThat(pool.remove(e1), is(false));
+        assertThat(pool.release(e1), is(false));
+    }
+
+    @Test
+    public void testCloseBeforeRelease()
+    {
+        Pool<String> pool = new Pool<>(1,0);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.size(), is(1));
+        pool.close();
+        assertThat(pool.size(), is(0));
+        assertThat(pool.release(e1), is(false));
+    }
+
+    @Test
+    public void testMaxPoolSize()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        assertThat(pool.size(), is(0));
+        assertThat(pool.reserve(-1), notNullValue());
+        assertThat(pool.size(), is(1));
+        assertThat(pool.reserve(-1), nullValue());
+        assertThat(pool.size(), is(1));
+    }
+
+    @Test
+    public void testReserve()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+        Pool<String>.Entry entry = pool.reserve(-1);
+        assertThat(pool.size(), is(1));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(entry.isClosed(), is(true));
+
+        assertThrows(NullPointerException.class, () -> entry.enable(null));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(entry.isClosed(), is(true));
+
+        entry.enable("aaa");
+        assertThat(entry.isClosed(), is(false));
+        assertThat(pool.acquire().getPooled(), notNullValue());
+
+        assertThrows(IllegalStateException.class, () -> entry.enable("bbb"));
+
+        Pool<String>.Entry e2 = pool.reserve(-1);
+        assertThat(pool.size(), is(2));
+        assertThat(pool.remove(e2), is(true));
+        assertThat(pool.size(), is(1));
+
+        pool.reserve(-1);
+        assertThat(pool.size(), is(2));
+        pool.close();
+        assertThat(pool.size(), is(0));
+        assertThat(pool.reserve(-1), nullValue());
+        assertThat(entry.isClosed(), is(true));
+    }
+
+    @Test
+    public void testReserveMaxPending()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+        assertThat(pool.reserve(0), nullValue());
+        assertThat(pool.reserve(1), notNullValue());
+        assertThat(pool.reserve(1), nullValue());
+        assertThat(pool.reserve(2), notNullValue());
+        assertThat(pool.reserve(2), nullValue());
+        assertThat(pool.reserve(3), nullValue());
+        assertThat(pool.reserve(-1), nullValue());
+    }
+
+    @Test
+    public void testReserveNegativeMaxPending()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+        assertThat(pool.reserve(-1), notNullValue());
+        assertThat(pool.reserve(-1), notNullValue());
+        assertThat(pool.reserve(-1), nullValue());
+    }
+
+    @Test
+    public void testClose()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.reserve(-1).enable("aaa");
+        assertThat(pool.isClosed(), is(false));
+        pool.close();
+        pool.close();
+
+        assertThat(pool.isClosed(), is(true));
+        assertThat(pool.size(), is(0));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(pool.reserve(-1), nullValue());
+    }
+
+    @Test
+    public void testClosingCloseable()
+    {
+        AtomicBoolean closed = new AtomicBoolean();
+        Pool<Closeable> pool = new Pool<>(1,0);
+        Closeable pooled = () -> closed.set(true);
+        pool.reserve(-1).enable(pooled);
+        assertThat(closed.get(), is(false));
+        pool.close();
+        assertThat(closed.get(), is(true));
+    }
+
+    @Test
+    public void testRemove()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.remove(e1), is(true));
+        assertThat(pool.remove(e1), is(false));
+        assertThat(pool.release(e1), is(false));
+        assertThat(pool.acquire(), nullValue());
+        assertThrows(NullPointerException.class, () -> pool.remove(null));
+    }
+
+    @Test
+    public void testValuesSize()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+
+        assertThat(pool.size(), is(0));
+        assertThat(pool.values().isEmpty(), is(true));
+        pool.reserve(-1).enable("aaa");
+        pool.reserve(-1).enable("bbb");
+        assertThat(pool.values().stream().map(Pool.Entry::getPooled).collect(toList()), equalTo(Arrays.asList("aaa", "bbb")));
+        assertThat(pool.size(), is(2));
+    }
+
+    @Test
+    public void testValuesContainsAcquiredEntries()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+
+        pool.reserve(-1).enable("aaa");
+        pool.reserve(-1).enable("bbb");
+        assertThat(pool.acquire(), notNullValue());
+        assertThat(pool.acquire(), notNullValue());
+        assertThat(pool.acquire(), nullValue());
+        assertThat(pool.values().isEmpty(), is(false));
+    }
+
+    @Test
+    public void testAcquireAt()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+
+        pool.reserve(-1).enable("aaa");
+        pool.reserve(-1).enable("bbb");
+
+        assertThat(pool.acquireAt(2), nullValue());
+        assertThat(pool.acquireAt(0), notNullValue());
+        assertThat(pool.acquireAt(0), nullValue());
+        assertThat(pool.acquireAt(1), notNullValue());
+        assertThat(pool.acquireAt(1), nullValue());
+    }
+
+    @Test
+    public void testMaxUsageCount()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxUsageCount(3);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.release(e1), is(true));
+        e1 = pool.acquire();
+        assertThat(pool.release(e1), is(true));
+        e1 = pool.acquire();
+        assertThat(pool.release(e1), is(false));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(pool.size(), is(1));
+        assertThat(pool.remove(e1), is(true));
+        assertThat(pool.remove(e1), is(false));
+        assertThat(pool.size(), is(0));
+        Pool<String>.Entry e1Copy = e1;
+        assertThat(pool.release(e1Copy), is(false));
+    }
+
+    @Test
+    public void testMaxMultiplex()
+    {
+        Pool<String> pool = new Pool<>(2, 0);
+        pool.setMaxMultiplex(3);
+        pool.reserve(-1).enable("aaa");
+        pool.reserve(-1).enable("bbb");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        Pool<String>.Entry e2 = pool.acquire();
+        Pool<String>.Entry e3 = pool.acquire();
+        Pool<String>.Entry e4 = pool.acquire();
+        assertThat(e1.getPooled(), equalTo("aaa"));
+        assertThat(e1, sameInstance(e2));
+        assertThat(e1, sameInstance(e3));
+        assertThat(e4.getPooled(), equalTo("bbb"));
+        assertThat(pool.release(e1), is(true));
+        Pool<String>.Entry e5 = pool.acquire();
+        assertThat(e2, sameInstance(e5));
+        Pool<String>.Entry e6 = pool.acquire();
+        assertThat(e4, sameInstance(e6));
+    }
+
+    @Test
+    public void testRemoveMultiplexed()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        Pool<String>.Entry e2 = pool.acquire();
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(false));
+
+        assertThat(pool.remove(e1), is(false));
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(false));
+        assertThat(pool.values().stream().findFirst().get().isClosed(), is(true));
+        assertThat(pool.remove(e1), is(true));
+        assertThat(pool.size(), is(0));
+
+        assertThat(pool.remove(e1), is(false));
+
+        assertThat(pool.release(e1), is(false));
+
+        assertThat(pool.remove(e1), is(false));
+    }
+
+    @Test
+    public void testMultiplexRemoveThenAcquireThenReleaseRemove()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        Pool<String>.Entry e2 = pool.acquire();
+
+        assertThat(pool.remove(e1), is(false));
+        assertThat(e1.isClosed(), is(true));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(pool.release(e2), is(false));
+        assertThat(pool.remove(e2), is(true));
+    }
+
+    @Test
+    public void testNonMultiplexRemoveAfterAcquire()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.remove(e1), is(true));
+        assertThat(pool.size(), is(0));
+    }
+
+    @Test
+    public void testMultiplexRemoveAfterAcquire()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        Pool<String>.Entry e2 = pool.acquire();
+
+        assertThat(pool.remove(e1), is(false));
+        assertThat(pool.remove(e2), is(true));
+        assertThat(pool.size(), is(0));
+
+        assertThat(pool.release(e1), is(false));
+        assertThat(pool.size(), is(0));
+
+        Pool<String>.Entry e3 = pool.acquire();
+        assertThat(e3, nullValue());
+
+        assertThat(pool.release(e2), is(false));
+        assertThat(pool.size(), is(0));
+    }
+
+    @Test
+    public void testReleaseThenRemoveNonEnabledEntry()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        Pool<String>.Entry e = pool.reserve(-1);
+        assertThat(pool.size(), is(1));
+        assertThat(pool.release(e), is(false));
+        assertThat(pool.size(), is(1));
+        assertThat(pool.remove(e), is(true));
+        assertThat(pool.size(), is(0));
+    }
+
+    @Test
+    public void testRemoveNonEnabledEntry()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        Pool<String>.Entry e = pool.reserve(-1);
+        assertThat(pool.size(), is(1));
+        assertThat(pool.remove(e), is(true));
+        assertThat(pool.size(), is(0));
+    }
+
+    @Test
+    public void testMultiplexMaxUsageReachedAcquireThenRemove()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.setMaxUsageCount(3);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e0 = pool.acquire();
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.release(e1), is(true));
+        Pool<String>.Entry e2 = pool.acquire();
+        assertThat(pool.release(e2), is(true));
+        assertThat(pool.acquire(), nullValue());
+
+        assertThat(pool.remove(e0), is(true));
+        assertThat(pool.size(), is(0));
+    }
+    
+    @Test
+    public void testMultiplexMaxUsageReachedAcquireThenReleaseThenRemove()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.setMaxUsageCount(3);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e0 = pool.acquire();
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(pool.release(e1), is(true));
+        Pool<String>.Entry e2 = pool.acquire();
+        assertThat(pool.release(e2), is(true));
+        assertThat(pool.acquire(), nullValue());
+
+        assertThat(pool.release(e0), is(false));
+        assertThat(pool.values().stream().findFirst().get().isIdle(), is(true));
+        assertThat(pool.values().stream().findFirst().get().isClosed(), is(false));
+        assertThat(pool.size(), is(1));
+        assertThat(pool.remove(e0), is(true));
+        assertThat(pool.size(), is(0));
+    }
+
+    @Test
+    public void testUsageCountAfterReachingMaxMultiplexLimit()
+    {
+        Pool<String> pool = new Pool<>(1, 0);
+        pool.setMaxMultiplex(2);
+        pool.setMaxUsageCount(10);
+        pool.reserve(-1).enable("aaa");
+
+        Pool<String>.Entry e1 = pool.acquire();
+        assertThat(e1.getUsageCount(), is(1));
+        Pool<String>.Entry e2 = pool.acquire();
+        assertThat(e1.getUsageCount(), is(2));
+        assertThat(pool.acquire(), nullValue());
+        assertThat(e1.getUsageCount(), is(2));
+    }
+
+    @Test
+    public void testConfigLimits()
+    {
+        assertThrows(IllegalArgumentException.class, () -> new Pool<String>(1, 0).setMaxMultiplex(0));
+        assertThrows(IllegalArgumentException.class, () -> new Pool<String>(1, 0).setMaxMultiplex(-1));
+        assertThrows(IllegalArgumentException.class, () -> new Pool<String>(1, 0).setMaxUsageCount(0));
+    }
+}

jetty-util/src/test/java/org/eclipse/jetty/util/URIUtilCanonicalPathTest.java

@@ -114,6 +114,13 @@ public class URIUtilCanonicalPathTest
                 // paths with encoded segments should remain encoded
                 // canonicalPath() is not responsible for decoding characters
                 {"%2e%2e/", "%2e%2e/"},
+                {"/%2e%2e/", "/%2e%2e/"},
+
+                // paths with parameters are not elided
+                // canonicalPath() is not responsible for decoding characters
+                {"/foo/.;/bar", "/foo/.;/bar"},
+                {"/foo/..;/bar", "/foo/..;/bar"},
+                {"/foo/..;/..;/bar", "/foo/..;/..;/bar"},
             };
 
         ArrayList<Arguments> ret = new ArrayList<>();

jetty-util/src/test/java/org/eclipse/jetty/util/URLEncodedTest.java

@@ -24,15 +24,21 @@ import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.stream.Stream;
 
 import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestFactory;
 import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.DynamicTest.dynamicTest;
 
@@ -49,97 +55,97 @@ public class URLEncodedTest
 
         tests.add(dynamicTest("Initially not empty", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             assertEquals(0, urlEncoded.size());
         }));
 
         tests.add(dynamicTest("Not empty after decode(\"\")", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("");
+            UrlEncoded.decodeTo("", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(0, urlEncoded.size());
         }));
 
         tests.add(dynamicTest("Simple encode", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name1=Value1");
+            UrlEncoded.decodeTo("Name1=Value1", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "simple param size");
-            assertEquals("Name1=Value1", urlEncoded.encode(), "simple encode");
+            assertEquals("Name1=Value1", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "simple encode");
             assertEquals("Value1", urlEncoded.getString("Name1"), "simple get");
         }));
 
         tests.add(dynamicTest("Dangling param", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name2=");
+            UrlEncoded.decodeTo("Name2=", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "dangling param size");
-            assertEquals("Name2", urlEncoded.encode(), "dangling encode");
+            assertEquals("Name2", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "dangling encode");
             assertEquals("", urlEncoded.getString("Name2"), "dangling get");
         }));
 
         tests.add(dynamicTest("noValue param", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name3");
+            UrlEncoded.decodeTo("Name3", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "noValue param size");
-            assertEquals("Name3", urlEncoded.encode(), "noValue encode");
+            assertEquals("Name3", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "noValue encode");
             assertEquals("", urlEncoded.getString("Name3"), "noValue get");
         }));
 
         tests.add(dynamicTest("badly encoded param", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name4=V\u0629lue+4%21");
+            UrlEncoded.decodeTo("Name4=V\u0629lue+4%21", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "encoded param size");
-            assertEquals("Name4=V%D8%A9lue+4%21", urlEncoded.encode(), "encoded encode");
+            assertEquals("Name4=V%D8%A9lue+4%21", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "encoded encode");
             assertEquals("V\u0629lue 4!", urlEncoded.getString("Name4"), "encoded get");
         }));
 
         tests.add(dynamicTest("encoded param 1", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name4=Value%2B4%21");
+            UrlEncoded.decodeTo("Name4=Value%2B4%21", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "encoded param size");
-            assertEquals("Name4=Value%2B4%21", urlEncoded.encode(), "encoded encode");
+            assertEquals("Name4=Value%2B4%21", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "encoded encode");
             assertEquals("Value+4!", urlEncoded.getString("Name4"), "encoded get");
         }));
 
         tests.add(dynamicTest("encoded param 2", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name4=Value+4%21%20%214");
+            UrlEncoded.decodeTo("Name4=Value+4%21%20%214", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "encoded param size");
-            assertEquals("Name4=Value+4%21+%214", urlEncoded.encode(), "encoded encode");
+            assertEquals("Name4=Value+4%21+%214", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "encoded encode");
             assertEquals("Value 4! !4", urlEncoded.getString("Name4"), "encoded get");
         }));
 
         tests.add(dynamicTest("multi param", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name5=aaa&Name6=bbb");
+            UrlEncoded.decodeTo("Name5=aaa&Name6=bbb", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(2, urlEncoded.size(), "multi param size");
-            assertTrue(urlEncoded.encode().equals("Name5=aaa&Name6=bbb") ||
-                    urlEncoded.encode().equals("Name6=bbb&Name5=aaa"),
-                "multi encode " + urlEncoded.encode());
+            assertTrue(UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false).equals("Name5=aaa&Name6=bbb") ||
+                    UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false).equals("Name6=bbb&Name5=aaa"),
+                "multi encode " + UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false));
             assertEquals("aaa", urlEncoded.getString("Name5"), "multi get");
             assertEquals("bbb", urlEncoded.getString("Name6"), "multi get");
         }));
 
         tests.add(dynamicTest("multiple value encoded", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name7=aaa&Name7=b%2Cb&Name7=ccc");
-            assertEquals("Name7=aaa&Name7=b%2Cb&Name7=ccc", urlEncoded.encode(), "multi encode");
+            UrlEncoded.decodeTo("Name7=aaa&Name7=b%2Cb&Name7=ccc", urlEncoded, UrlEncoded.ENCODING);
+            assertEquals("Name7=aaa&Name7=b%2Cb&Name7=ccc", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "multi encode");
             assertEquals("aaa,b,b,ccc", urlEncoded.getString("Name7"), "list get all");
             assertEquals("aaa", urlEncoded.getValues("Name7").get(0), "list get");
             assertEquals("b,b", urlEncoded.getValues("Name7").get(1), "list get");
@@ -148,11 +154,11 @@ public class URLEncodedTest
 
         tests.add(dynamicTest("encoded param", () ->
         {
-            UrlEncoded urlEncoded = new UrlEncoded();
+            MultiMap<String> urlEncoded = new MultiMap<>();
             urlEncoded.clear();
-            urlEncoded.decode("Name8=xx%2C++yy++%2Czz");
+            UrlEncoded.decodeTo("Name8=xx%2C++yy++%2Czz", urlEncoded, UrlEncoded.ENCODING);
             assertEquals(1, urlEncoded.size(), "encoded param size");
-            assertEquals("Name8=xx%2C++yy++%2Czz", urlEncoded.encode(), "encoded encode");
+            assertEquals("Name8=xx%2C++yy++%2Czz", UrlEncoded.encode(urlEncoded,UrlEncoded.ENCODING, false), "encoded encode");
             assertEquals("xx,  yy  ,zz", urlEncoded.getString("Name8"), "encoded get");
         }));
 
@@ -219,7 +225,7 @@ public class URLEncodedTest
     {
         try (ByteArrayInputStream in3 = new ByteArrayInputStream("name=libell%E9".getBytes(StringUtil.__ISO_8859_1)))
         {
-            MultiMap m3 = new MultiMap();
+            MultiMap<String> m3 = new MultiMap<>();
             Charset nullCharset = null; // use the one from the system property
             UrlEncoded.decodeTo(in3, m3, nullCharset, -1, -1);
             assertEquals("libell\u00E9", m3.getString("name"), "stream name");
@@ -230,11 +236,11 @@ public class URLEncodedTest
     public void testUtf8()
         throws Exception
     {
-        UrlEncoded urlEncoded = new UrlEncoded();
+        MultiMap<String> urlEncoded = new MultiMap<>();
         assertEquals(0, urlEncoded.size(), "Empty");
 
         urlEncoded.clear();
-        urlEncoded.decode("text=%E0%B8%9F%E0%B8%AB%E0%B8%81%E0%B8%A7%E0%B8%94%E0%B8%B2%E0%B9%88%E0%B8%81%E0%B8%9F%E0%B8%A7%E0%B8%AB%E0%B8%AA%E0%B8%94%E0%B8%B2%E0%B9%88%E0%B8%AB%E0%B8%9F%E0%B8%81%E0%B8%A7%E0%B8%94%E0%B8%AA%E0%B8%B2%E0%B8%9F%E0%B8%81%E0%B8%AB%E0%B8%A3%E0%B8%94%E0%B9%89%E0%B8%9F%E0%B8%AB%E0%B8%99%E0%B8%81%E0%B8%A3%E0%B8%94%E0%B8%B5&Action=Submit");
+        UrlEncoded.decodeTo("text=%E0%B8%9F%E0%B8%AB%E0%B8%81%E0%B8%A7%E0%B8%94%E0%B8%B2%E0%B9%88%E0%B8%81%E0%B8%9F%E0%B8%A7%E0%B8%AB%E0%B8%AA%E0%B8%94%E0%B8%B2%E0%B9%88%E0%B8%AB%E0%B8%9F%E0%B8%81%E0%B8%A7%E0%B8%94%E0%B8%AA%E0%B8%B2%E0%B8%9F%E0%B8%81%E0%B8%AB%E0%B8%A3%E0%B8%94%E0%B9%89%E0%B8%9F%E0%B8%AB%E0%B8%99%E0%B8%81%E0%B8%A3%E0%B8%94%E0%B8%B5&Action=Submit", urlEncoded, UrlEncoded.ENCODING);
 
         String hex = "E0B89FE0B8ABE0B881E0B8A7E0B894E0B8B2E0B988E0B881E0B89FE0B8A7E0B8ABE0B8AAE0B894E0B8B2E0B988E0B8ABE0B89FE0B881E0B8A7E0B894E0B8AAE0B8B2E0B89FE0B881E0B8ABE0B8A3E0B894E0B989E0B89FE0B8ABE0B899E0B881E0B8A3E0B894E0B8B5";
         String expected = new String(TypeUtil.fromHexString(hex), "utf-8");
@@ -245,8 +251,8 @@ public class URLEncodedTest
     public void testUtf8MultiByteCodePoint()
     {
         String input = "text=test%C3%A4";
-        UrlEncoded urlEncoded = new UrlEncoded();
-        urlEncoded.decode(input);
+        MultiMap<String> urlEncoded = new MultiMap<>();
+        UrlEncoded.decodeTo(input, urlEncoded, UrlEncoded.ENCODING);
 
         // http://www.ltg.ed.ac.uk/~richard/utf-8.cgi?input=00e4&mode=hex
         // Should be "testä"
@@ -255,4 +261,50 @@ public class URLEncodedTest
         String expected = "test\u00e4";
         assertThat(urlEncoded.getString("text"), is(expected));
     }
+
+    public static Stream<Arguments> invalidTestData()
+    {
+        ArrayList<Arguments> data = new ArrayList<>();
+        data.add(Arguments.of("Name=xx%zzyy", UTF_8, IllegalArgumentException.class));
+        data.add(Arguments.of("Name=%FF%FF%FF", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        data.add(Arguments.of("Name=%EF%EF%EF", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        data.add(Arguments.of("Name=%E%F%F", UTF_8, IllegalArgumentException.class));
+        data.add(Arguments.of("Name=x%", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        data.add(Arguments.of("Name=x%2", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        data.add(Arguments.of("Name=xxx%", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        data.add(Arguments.of("name=X%c0%afZ", UTF_8, Utf8Appendable.NotUtf8Exception.class));
+        return data.stream();
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestData")
+    public void testInvalidDecode(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
+    {
+        assertThrows(expectedThrowable, () ->
+        {
+            UrlEncoded.decodeTo(inputString, new MultiMap<>(), charset);
+        });
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestData")
+    public void testInvalidDecodeUtf8ToMap(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
+    {
+        assertThrows(expectedThrowable, () ->
+        {
+            MultiMap<String> map = new MultiMap<>();
+            UrlEncoded.decodeUtf8To(inputString, map);
+        });
+    }
+
+    @ParameterizedTest
+    @MethodSource("invalidTestData")
+    public void testInvalidDecodeTo(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
+    {
+        assertThrows(expectedThrowable, () ->
+        {
+            MultiMap<String> map = new MultiMap<>();
+            UrlEncoded.decodeTo(inputString, map, charset);
+        });
+    }
 }

jetty-util/src/test/java/org/eclipse/jetty/util/UrlEncodedInvalidEncodingTest.java

@@ -1,80 +0,0 @@
-//
-// ========================================================================
-// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
-//
-// This program and the accompanying materials are made available under
-// the terms of the Eclipse Public License 2.0 which is available at
-// https://www.eclipse.org/legal/epl-2.0
-//
-// This Source Code may also be made available under the following
-// Secondary Licenses when the conditions for such availability set
-// forth in the Eclipse Public License, v. 2.0 are satisfied:
-// the Apache License v2.0 which is available at
-// https://www.apache.org/licenses/LICENSE-2.0
-//
-// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
-// ========================================================================
-//
-
-package org.eclipse.jetty.util;
-
-import java.nio.charset.Charset;
-import java.util.ArrayList;
-import java.util.stream.Stream;
-
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.MethodSource;
-
-import static java.nio.charset.StandardCharsets.UTF_8;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-public class UrlEncodedInvalidEncodingTest
-{
-    public static Stream<Arguments> data()
-    {
-        ArrayList<Arguments> data = new ArrayList<>();
-        data.add(Arguments.of("Name=xx%zzyy", UTF_8, IllegalArgumentException.class));
-        data.add(Arguments.of("Name=%FF%FF%FF", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        data.add(Arguments.of("Name=%EF%EF%EF", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        data.add(Arguments.of("Name=%E%F%F", UTF_8, IllegalArgumentException.class));
-        data.add(Arguments.of("Name=x%", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        data.add(Arguments.of("Name=x%2", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        data.add(Arguments.of("Name=xxx%", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        data.add(Arguments.of("name=X%c0%afZ", UTF_8, Utf8Appendable.NotUtf8Exception.class));
-        return data.stream();
-    }
-
-    @ParameterizedTest
-    @MethodSource("data")
-    public void testDecode(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
-    {
-        assertThrows(expectedThrowable, () ->
-        {
-            UrlEncoded urlEncoded = new UrlEncoded();
-            urlEncoded.decode(inputString, charset);
-        });
-    }
-
-    @ParameterizedTest
-    @MethodSource("data")
-    public void testDecodeUtf8ToMap(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
-    {
-        assertThrows(expectedThrowable, () ->
-        {
-            MultiMap<String> map = new MultiMap<>();
-            UrlEncoded.decodeUtf8To(inputString, map);
-        });
-    }
-
-    @ParameterizedTest
-    @MethodSource("data")
-    public void testDecodeTo(String inputString, Charset charset, Class<? extends Throwable> expectedThrowable)
-    {
-        assertThrows(expectedThrowable, () ->
-        {
-            MultiMap<String> map = new MultiMap<>();
-            UrlEncoded.decodeTo(inputString, map, charset);
-        });
-    }
-}

jetty-webapp/src/main/java/org/eclipse/jetty/webapp/WebAppContext.java

@@ -1314,7 +1314,6 @@ public class WebAppContext extends ServletContextHandler implements WebAppClassL
                 setClassLoader(null);
             }
 
-            setAvailable(true);
             _unavailableException = null;
         }
     }

jetty-websocket/websocket-javax-common/src/main/java/org/eclipse/jetty/websocket/javax/common/JavaxWebSocketContainer.java

@@ -40,8 +40,8 @@ import org.slf4j.LoggerFactory;
 public abstract class JavaxWebSocketContainer extends ContainerLifeCycle implements javax.websocket.WebSocketContainer
 {
     private static final Logger LOG = LoggerFactory.getLogger(JavaxWebSocketContainer.class);
-    private final SessionTracker sessionTracker = new SessionTracker();
     private final List<JavaxWebSocketSessionListener> sessionListeners = new ArrayList<>();
+    protected final SessionTracker sessionTracker = new SessionTracker();
     protected final Configuration.ConfigurationCustomizer defaultCustomizer = new Configuration.ConfigurationCustomizer();
     protected final WebSocketComponents components;
 

jetty-websocket/websocket-javax-common/src/main/java/org/eclipse/jetty/websocket/javax/common/SessionTracker.java

@@ -18,26 +18,26 @@
 
 package org.eclipse.jetty.websocket.javax.common;
 
-import java.io.IOException;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 import javax.websocket.CloseReason;
 import javax.websocket.Session;
 
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.eclipse.jetty.util.component.Graceful;
 
-public class SessionTracker extends AbstractLifeCycle implements JavaxWebSocketSessionListener
+public class SessionTracker extends AbstractLifeCycle implements JavaxWebSocketSessionListener, Graceful
 {
-    private static final Logger LOG = LoggerFactory.getLogger(SessionTracker.class);
-
-    private final CopyOnWriteArraySet<JavaxWebSocketSession> sessions = new CopyOnWriteArraySet<>();
+    private final Set<JavaxWebSocketSession> sessions = Collections.newSetFromMap(new ConcurrentHashMap<>());
+    private boolean isShutdown = false;
 
     public Set<Session> getSessions()
     {
-        return Collections.unmodifiableSet(sessions);
+        return Set.copyOf(sessions);
     }
 
     @Override
@@ -52,22 +52,40 @@ public class SessionTracker extends AbstractLifeCycle implements JavaxWebSocketS
         sessions.remove(session);
     }
 
+    @Override
+    protected void doStart() throws Exception
+    {
+        isShutdown = false;
+        super.doStart();
+    }
+
     @Override
     protected void doStop() throws Exception
     {
-        for (Session session : sessions)
+        sessions.clear();
+        super.doStop();
+    }
+
+    @Override
+    public CompletableFuture<Void> shutdown()
+    {
+        isShutdown = true;
+        return Graceful.shutdown(() ->
         {
-            try
+            for (Session session : sessions)
             {
+                if (Thread.interrupted())
+                    break;
+
                 // GOING_AWAY is abnormal close status so it will hard close connection after sent.
                 session.close(new CloseReason(CloseReason.CloseCodes.GOING_AWAY, "Container being shut down"));
             }
-            catch (IOException e)
-            {
-                LOG.trace("IGNORED", e);
-            }
-        }
+        });
+    }
 
-        super.doStop();
+    @Override
+    public boolean isShutdown()
+    {
+        return isShutdown;
     }
 }

jetty-websocket/websocket-javax-tests/src/main/java/org/eclipse/jetty/websocket/javax/tests/EchoSocket.java

@@ -0,0 +1,43 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.websocket.javax.tests;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import javax.websocket.ClientEndpoint;
+import javax.websocket.server.ServerEndpoint;
+
+@ServerEndpoint("/")
+@ClientEndpoint
+public class EchoSocket extends EventSocket
+{
+    @Override
+    public void onMessage(String message) throws IOException
+    {
+        super.onMessage(message);
+        session.getBasicRemote().sendText(message);
+    }
+
+    @Override
+    public void onMessage(ByteBuffer message) throws IOException
+    {
+        super.onMessage(message);
+        session.getBasicRemote().sendBinary(message);
+    }
+}

jetty-websocket/websocket-javax-tests/src/main/java/org/eclipse/jetty/websocket/javax/tests/EventSocket.java

@@ -98,23 +98,4 @@ public class EventSocket
         error = cause;
         errorLatch.countDown();
     }
-
-    @ServerEndpoint("/")
-    @ClientEndpoint
-    public static class EchoSocket extends EventSocket
-    {
-        @Override
-        public void onMessage(String message) throws IOException
-        {
-            super.onMessage(message);
-            session.getBasicRemote().sendText(message);
-        }
-
-        @Override
-        public void onMessage(ByteBuffer message) throws IOException
-        {
-            super.onMessage(message);
-            session.getBasicRemote().sendBinary(message);
-        }
-    }
 }

jetty-websocket/websocket-javax-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/GracefulCloseTest.java

@@ -0,0 +1,133 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.websocket.javax.tests;
+
+import java.net.URI;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+import javax.websocket.CloseReason;
+import javax.websocket.EndpointConfig;
+import javax.websocket.Session;
+import javax.websocket.server.ServerEndpoint;
+
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.servlet.ServletContextHandler;
+import org.eclipse.jetty.util.BlockingArrayQueue;
+import org.eclipse.jetty.util.component.Graceful;
+import org.eclipse.jetty.websocket.javax.client.internal.JavaxWebSocketClientContainer;
+import org.eclipse.jetty.websocket.javax.server.config.JavaxWebSocketServletContainerInitializer;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class GracefulCloseTest
+{
+    private static final BlockingArrayQueue<EventSocket> serverEndpoints = new BlockingArrayQueue<>();
+    private Server server;
+    private URI serverUri;
+    private JavaxWebSocketClientContainer client;
+
+    @BeforeEach
+    public void before() throws Exception
+    {
+        server = new Server();
+        ServerConnector connector = new ServerConnector(server);
+        server.addConnector(connector);
+
+        ServletContextHandler contextHandler = new ServletContextHandler();
+        contextHandler.setContextPath("/");
+        server.setHandler(contextHandler);
+        JavaxWebSocketServletContainerInitializer.configure(contextHandler, (context, container) ->
+            container.addEndpoint(ServerSocket.class));
+        server.start();
+        serverUri = WSURI.toWebsocket(server.getURI());
+
+        // StopTimeout is necessary for the websocket server sessions to gracefully close.
+        server.setStopTimeout(1000);
+
+        client = new JavaxWebSocketClientContainer();
+        client.start();
+    }
+
+    @AfterEach
+    public void after() throws Exception
+    {
+        client.stop();
+        server.stop();
+    }
+
+    @ServerEndpoint("/")
+    public static class ServerSocket extends EchoSocket
+    {
+        @Override
+        public void onOpen(Session session, EndpointConfig endpointConfig)
+        {
+            serverEndpoints.add(this);
+            super.onOpen(session, endpointConfig);
+        }
+    }
+
+    @Test
+    public void testClientStop() throws Exception
+    {
+        EventSocket clientEndpoint = new EventSocket();
+        client.connectToServer(clientEndpoint, serverUri);
+        EventSocket serverEndpoint = Objects.requireNonNull(serverEndpoints.poll(5, TimeUnit.SECONDS));
+
+        // There is no API for a Javax WebSocketContainer stop timeout.
+        Graceful.shutdown(client).get(5, TimeUnit.SECONDS);
+        client.stop();
+
+        // Check that the client endpoint was closed with the correct status code and no error.
+        assertTrue(clientEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(clientEndpoint.closeReason.getCloseCode(), is(CloseReason.CloseCodes.GOING_AWAY));
+        assertNull(clientEndpoint.error);
+
+        // Check that the server endpoint was closed with the correct status code and no error.
+        assertTrue(serverEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(serverEndpoint.closeReason.getCloseCode(), is(CloseReason.CloseCodes.GOING_AWAY));
+        assertNull(serverEndpoint.error);
+    }
+
+    @Test
+    public void testServerStop() throws Exception
+    {
+        EventSocket clientEndpoint = new EventSocket();
+        client.connectToServer(clientEndpoint, serverUri);
+        EventSocket serverEndpoint = Objects.requireNonNull(serverEndpoints.poll(5, TimeUnit.SECONDS));
+
+        server.stop();
+
+        // Check that the client endpoint was closed with the correct status code and no error.
+        assertTrue(clientEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(clientEndpoint.closeReason.getCloseCode(), is(CloseReason.CloseCodes.GOING_AWAY));
+        assertNull(clientEndpoint.error);
+
+        // Check that the server endpoint was closed with the correct status code and no error.
+        assertTrue(serverEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(serverEndpoint.closeReason.getCloseCode(), is(CloseReason.CloseCodes.GOING_AWAY));
+        assertNull(serverEndpoint.error);
+    }
+}

jetty-websocket/websocket-javax-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/coders/EncoderLifeCycleTest.java

@@ -40,7 +40,7 @@ import org.eclipse.jetty.util.BlockingArrayQueue;
 import org.eclipse.jetty.websocket.javax.common.JavaxWebSocketSession;
 import org.eclipse.jetty.websocket.javax.common.encoders.AvailableEncoders;
 import org.eclipse.jetty.websocket.javax.server.config.JavaxWebSocketServletContainerInitializer;
-import org.eclipse.jetty.websocket.javax.tests.EventSocket.EchoSocket;
+import org.eclipse.jetty.websocket.javax.tests.EchoSocket;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.params.ParameterizedTest;

jetty-websocket/websocket-jetty-client/src/main/java/org/eclipse/jetty/websocket/client/WebSocketClient.java

@@ -29,6 +29,7 @@ import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 
 import org.eclipse.jetty.client.HttpClient;
@@ -38,6 +39,7 @@ import org.eclipse.jetty.io.ByteBufferPool;
 import org.eclipse.jetty.io.Connection;
 import org.eclipse.jetty.util.DecoratedObjectFactory;
 import org.eclipse.jetty.util.component.ContainerLifeCycle;
+import org.eclipse.jetty.util.component.Graceful;
 import org.eclipse.jetty.util.ssl.SslContextFactory;
 import org.eclipse.jetty.util.thread.ShutdownThread;
 import org.eclipse.jetty.websocket.api.Session;
@@ -68,6 +70,7 @@ public class WebSocketClient extends ContainerLifeCycle implements WebSocketPoli
     private final Configuration.ConfigurationCustomizer configurationCustomizer = new Configuration.ConfigurationCustomizer();
     private final WebSocketComponents components = new WebSocketComponents();
     private boolean stopAtShutdown = false;
+    private long _stopTimeout = Long.MAX_VALUE;
 
     /**
      * Instantiate a WebSocketClient with defaults
@@ -388,11 +391,33 @@ public class WebSocketClient extends ContainerLifeCycle implements WebSocketPoli
         stopAtShutdown = stop;
     }
 
+    /**
+     * The timeout to allow all remaining open Sessions to be closed gracefully using  the close code {@link org.eclipse.jetty.websocket.api.StatusCode#SHUTDOWN}.
+     * @param stopTimeout the time in ms to wait for the graceful close, use a value less than or equal to 0 to not gracefully close.
+     */
+    public void setStopTimeout(long stopTimeout)
+    {
+        _stopTimeout = stopTimeout;
+    }
+
+    public long getStopTimeout()
+    {
+        return _stopTimeout;
+    }
+
     public boolean isStopAtShutdown()
     {
         return stopAtShutdown;
     }
 
+    @Override
+    protected void doStop() throws Exception
+    {
+        if (getStopTimeout() > 0)
+            Graceful.shutdown(this).get(getStopTimeout(), TimeUnit.MILLISECONDS);
+        super.doStop();
+    }
+
     @Override
     public String toString()
     {

jetty-websocket/websocket-jetty-common/src/main/java/org/eclipse/jetty/websocket/common/SessionTracker.java

@@ -19,21 +19,28 @@
 package org.eclipse.jetty.websocket.common;
 
 import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
+import org.eclipse.jetty.util.component.Graceful;
 import org.eclipse.jetty.websocket.api.Session;
 import org.eclipse.jetty.websocket.api.StatusCode;
 import org.eclipse.jetty.websocket.api.WebSocketSessionListener;
 
-public class SessionTracker extends AbstractLifeCycle implements WebSocketSessionListener
+public class SessionTracker extends AbstractLifeCycle implements WebSocketSessionListener, Graceful
 {
-    private List<Session> sessions = new CopyOnWriteArrayList<>();
+    private final Set<Session> sessions = Collections.newSetFromMap(new ConcurrentHashMap<>());
+    private boolean isShutdown = false;
 
     public Collection<Session> getSessions()
     {
-        return sessions;
+        return Set.copyOf(sessions);
     }
 
     @Override
@@ -48,15 +55,40 @@ public class SessionTracker extends AbstractLifeCycle implements WebSocketSessio
         sessions.remove(session);
     }
 
+    @Override
+    protected void doStart() throws Exception
+    {
+        isShutdown = false;
+        super.doStart();
+    }
+
     @Override
     protected void doStop() throws Exception
     {
-        for (Session session : sessions)
-        {
-            // SHUTDOWN is abnormal close status so it will hard close connection after sent.
-            session.close(StatusCode.SHUTDOWN, "Container being shut down");
-        }
-
+        sessions.clear();
         super.doStop();
     }
+
+    @Override
+    public CompletableFuture<Void> shutdown()
+    {
+        isShutdown = true;
+        return Graceful.shutdown(() ->
+        {
+            for (Session session : sessions)
+            {
+                if (Thread.interrupted())
+                    break;
+
+                // SHUTDOWN is abnormal close status so it will hard close connection after sent.
+                session.close(StatusCode.SHUTDOWN, "Container being shut down");
+            }
+        });
+    }
+
+    @Override
+    public boolean isShutdown()
+    {
+        return isShutdown;
+    }
 }

jetty-websocket/websocket-jetty-server/src/main/java/org/eclipse/jetty/websocket/server/JettyWebSocketServerContainer.java

@@ -119,6 +119,7 @@ public class JettyWebSocketServerContainer extends ContainerLifeCycle implements
         frameHandlerFactory = factory;
 
         addSessionListener(sessionTracker);
+        addBean(sessionTracker);
     }
 
     public void addMapping(String pathSpec, JettyWebSocketCreator creator)

jetty-websocket/websocket-jetty-tests/src/test/java/org/eclipse/jetty/websocket/tests/GracefulCloseTest.java

@@ -0,0 +1,114 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.websocket.tests;
+
+import java.net.URI;
+import java.util.concurrent.TimeUnit;
+
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.servlet.ServletContextHandler;
+import org.eclipse.jetty.websocket.api.StatusCode;
+import org.eclipse.jetty.websocket.api.util.WSURI;
+import org.eclipse.jetty.websocket.client.WebSocketClient;
+import org.eclipse.jetty.websocket.server.config.JettyWebSocketServletContainerInitializer;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class GracefulCloseTest
+{
+    private final EventSocket serverEndpoint = new EchoSocket();
+    private Server server;
+    private URI serverUri;
+    private WebSocketClient client;
+
+    @BeforeEach
+    public void before() throws Exception
+    {
+        server = new Server();
+        ServerConnector connector = new ServerConnector(server);
+        server.addConnector(connector);
+
+        ServletContextHandler contextHandler = new ServletContextHandler();
+        contextHandler.setContextPath("/");
+        server.setHandler(contextHandler);
+        JettyWebSocketServletContainerInitializer.configure(contextHandler, (context, container) ->
+            container.addMapping("/", ((req, resp) -> serverEndpoint)));
+        server.start();
+        serverUri = WSURI.toWebsocket(server.getURI());
+
+        // StopTimeout is necessary for the websocket server sessions to gracefully close.
+        server.setStopTimeout(1000);
+
+        client = new WebSocketClient();
+        client.setStopTimeout(1000);
+        client.start();
+    }
+
+    @AfterEach
+    public void after() throws Exception
+    {
+        client.stop();
+        server.stop();
+    }
+
+    @Test
+    public void testClientStop() throws Exception
+    {
+        EventSocket clientEndpoint = new EventSocket();
+        client.connect(clientEndpoint, serverUri).get(5, TimeUnit.SECONDS);
+
+        client.stop();
+
+        // Check that the client endpoint was closed with the correct status code and no error.
+        assertTrue(clientEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(clientEndpoint.closeCode, is(StatusCode.SHUTDOWN));
+        assertNull(clientEndpoint.error);
+
+        // Check that the server endpoint was closed with the correct status code and no error.
+        assertTrue(serverEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(serverEndpoint.closeCode, is(StatusCode.SHUTDOWN));
+        assertNull(serverEndpoint.error);
+    }
+
+    @Test
+    public void testServerStop() throws Exception
+    {
+        EventSocket clientEndpoint = new EventSocket();
+        client.connect(clientEndpoint, serverUri).get(5, TimeUnit.SECONDS);
+
+        server.stop();
+
+        // Check that the client endpoint was closed with the correct status code and no error.
+        assertTrue(clientEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(clientEndpoint.closeCode, is(StatusCode.SHUTDOWN));
+        assertNull(clientEndpoint.error);
+
+        // Check that the server endpoint was closed with the correct status code and no error.
+        assertTrue(serverEndpoint.closeLatch.await(5, TimeUnit.SECONDS));
+        assertThat(serverEndpoint.closeCode, is(StatusCode.SHUTDOWN));
+        assertNull(serverEndpoint.error);
+    }
+}

tests/jetty-jmh/pom.xml

@@ -106,6 +106,11 @@
       <artifactId>jetty-slf4j-impl</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-client</artifactId>
+      <version>${project.version}</version>
+    </dependency>
     <dependency>
       <groupId>org.eclipse.jetty.toolchain</groupId>
       <artifactId>jetty-test-helper</artifactId>

tests/jetty-jmh/src/main/java/org/eclipse/jetty/client/jmh/ConnectionPoolsBenchmark.java

@@ -0,0 +1,174 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under
+// the terms of the Eclipse Public License 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0
+//
+// This Source Code may also be made available under the following
+// Secondary Licenses when the conditions for such availability set
+// forth in the Eclipse Public License, v. 2.0 are satisfied:
+// the Apache License v2.0 which is available at
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.client.jmh;
+
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.concurrent.ThreadLocalRandom;
+
+import org.eclipse.jetty.client.ConnectionPool;
+import org.eclipse.jetty.client.DuplexConnectionPool;
+import org.eclipse.jetty.client.HttpClient;
+import org.eclipse.jetty.client.HttpConversation;
+import org.eclipse.jetty.client.HttpDestination;
+import org.eclipse.jetty.client.HttpExchange;
+import org.eclipse.jetty.client.HttpRequest;
+import org.eclipse.jetty.client.MultiplexConnectionPool;
+import org.eclipse.jetty.client.Origin;
+import org.eclipse.jetty.client.RoundRobinConnectionPool;
+import org.eclipse.jetty.client.api.Connection;
+import org.eclipse.jetty.client.api.Request;
+import org.eclipse.jetty.client.api.Response;
+import org.eclipse.jetty.util.Attachable;
+import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.Promise;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.TearDown;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+@State(Scope.Benchmark)
+public class ConnectionPoolsBenchmark
+{
+    private ConnectionPool pool;
+
+    @Param({"round-robin", "cached/multiplex", "uncached/multiplex", "cached/duplex", "uncached/duplex"})
+    public static String POOL_TYPE;
+
+    @Setup
+    public void setUp() throws Exception
+    {
+        HttpClient httpClient = new HttpClient()
+        {
+            @Override
+            protected void newConnection(HttpDestination destination, Promise<Connection> promise)
+            {
+                promise.succeeded(new MockConnection());
+            }
+        };
+        HttpDestination httpDestination = new HttpDestination(httpClient, new Origin("http", "localhost", 8080))
+        {
+        };
+
+        HttpConversation httpConversation = new HttpConversation();
+        HttpRequest httpRequest = new HttpRequest(httpClient, httpConversation, new URI("http://localhost:8080")) {};
+        HttpExchange httpExchange = new HttpExchange(httpDestination, httpRequest, new ArrayList<>());
+        httpDestination.getHttpExchanges().add(httpExchange);
+
+        int initialConnections = 12;
+        int maxConnections = 100;
+        switch (POOL_TYPE)
+        {
+            case "uncached/duplex":
+                pool = new DuplexConnectionPool(httpDestination, maxConnections, false, Callback.NOOP);
+                pool.preCreateConnections(initialConnections).get();
+                break;
+            case "cached/duplex":
+                pool = new DuplexConnectionPool(httpDestination, maxConnections, true, Callback.NOOP);
+                pool.preCreateConnections(initialConnections).get();
+                break;
+            case "uncached/multiplex":
+                pool = new MultiplexConnectionPool(httpDestination, maxConnections,false, Callback.NOOP, 12);
+                pool.preCreateConnections(initialConnections).get();
+                break;
+            case "cached/multiplex":
+                pool = new MultiplexConnectionPool(httpDestination, maxConnections,true, Callback.NOOP, 12);
+                pool.preCreateConnections(initialConnections).get();
+                break;
+            case "round-robin":
+                pool = new RoundRobinConnectionPool(httpDestination, maxConnections, Callback.NOOP);
+                pool.preCreateConnections(maxConnections).get();
+                break;
+            default:
+                throw new AssertionError("Unknown pool type: " + POOL_TYPE);
+        }
+    }
+
+    @TearDown
+    public void tearDown()
+    {
+        pool.close();
+        pool = null;
+    }
+
+    @Benchmark
+    public void testPool()
+    {
+        Connection connection = pool.acquire(true);
+        if (connection == null && !POOL_TYPE.equals("round-robin"))
+            throw new AssertionError("from thread " + Thread.currentThread().getName());
+        Blackhole.consumeCPU(ThreadLocalRandom.current().nextInt(10, 20));
+        if (connection != null)
+            pool.release(connection);
+    }
+
+    public static void main(String[] args) throws RunnerException
+    {
+        Options opt = new OptionsBuilder()
+            .include(ConnectionPoolsBenchmark.class.getSimpleName())
+            .warmupIterations(3)
+            .measurementIterations(3)
+            .forks(1)
+            .threads(12)
+            //.addProfiler(LinuxPerfProfiler.class)
+            .build();
+
+        new Runner(opt).run();
+    }
+
+    static class MockConnection implements Connection, Attachable
+    {
+        private Object attachment;
+
+        @Override
+        public void close()
+        {
+        }
+
+        @Override
+        public boolean isClosed()
+        {
+            return false;
+        }
+
+        @Override
+        public void send(Request request, Response.CompleteListener listener)
+        {
+        }
+
+        @Override
+        public void setAttachment(Object obj)
+        {
+            this.attachment = obj;
+        }
+
+        @Override
+        public Object getAttachment()
+        {
+            return attachment;
+        }
+    }
+}

tests/test-webapps/test-jetty-webapp/src/main/java/com/acme/SessionDump.java

@@ -79,7 +79,7 @@ public class SessionDump extends HttpServlet
                 session = request.getSession(true);
                 session.setAttribute("test", "value");
                 session.setAttribute("obj", new ObjectAttributeValue(System.currentTimeMillis()));
-                session.setAttribute("WEBCL", new MultiMap());
+                session.setAttribute("WEBCL", new MultiMap<>());
             }
             else if (session != null)
             {
@@ -137,7 +137,7 @@ public class SessionDump extends HttpServlet
         else
         {
             if (session.getAttribute("WEBCL") == null)
-                session.setAttribute("WEBCL", new MultiMap());
+                session.setAttribute("WEBCL", new MultiMap<>());
             try
             {
                 out.println("<b>ID:</b> " + session.getId() + "<br/>");