480904 - jetty-util Loader simplification

The Loader has been simplified to now just be a switch between loading from the context loader,
the same loader as another class or the system loader.    Multiple loaders will never be tried.

A new runWithServerClassAccess(PriviledgedAction) method has been added to WebAppClassLoader, that
is now used during configuration for actions that need access to both the WEB-INF/lib classes and
the server classes (eg jetty-web.xml and env.xml).

The JMX MBean mechanism has also been modified to look for an MBean class in the same loader that
object came from before attempting the context loader (only if different).

examples/embedded/src/main/java/org/eclipse/jetty/embedded/OneWebApp.java

@@ -52,9 +52,8 @@ public class OneWebApp
         WebAppContext webapp = new WebAppContext();
         webapp.setContextPath("/");
         File warFile = new File(
-                "../../jetty-distribution/target/distribution/test/webapps/test/");
+                "../../tests/test-jmx/jmx-webapp/target/jmx-webapp");
         webapp.setWar(warFile.getAbsolutePath());
-        webapp.addAliasCheck(new AllowSymLinkAliasChecker());
 
         // A WebAppContext is a ContextHandler as well so it needs to be set to
         // the server so it is aware of where to send the appropriate requests.

jetty-annotations/src/main/java/org/eclipse/jetty/annotations/AnnotationParser.java

@@ -558,7 +558,7 @@ public class AnnotationParser
             if (!isParsed(className) || resolver.shouldOverride(className))
             {
                 className = className.replace('.', '/')+".class";
-                URL resource = Loader.getResource(this.getClass(), className);
+                URL resource = Loader.getResource(className);
                 if (resource!= null)
                 {
                     Resource r = Resource.newResource(resource);
@@ -593,7 +593,7 @@ public class AnnotationParser
                 if (!isParsed(cz.getName()) || resolver.shouldOverride(cz.getName()))
                 {
                     String nameAsResource = cz.getName().replace('.', '/')+".class";
-                    URL resource = Loader.getResource(this.getClass(), nameAsResource);
+                    URL resource = Loader.getResource(nameAsResource);
                     if (resource!= null)
                     {
                         Resource r = Resource.newResource(resource);
@@ -652,7 +652,7 @@ public class AnnotationParser
                 if ((resolver == null) || (!resolver.isExcluded(s) &&  (!isParsed(s) || resolver.shouldOverride(s))))
                 {
                     s = s.replace('.', '/')+".class";
-                    URL resource = Loader.getResource(this.getClass(), s);
+                    URL resource = Loader.getResource(s);
                     if (resource!= null)
                     {
                         Resource r = Resource.newResource(resource);

jetty-annotations/src/main/java/org/eclipse/jetty/annotations/Util.java

@@ -201,7 +201,7 @@ public class Util
             }
             case Type.OBJECT:
             {
-                return (Loader.loadClass(null, t.getClassName()));
+                return (Loader.loadClass(t.getClassName()));
             }
             case Type.SHORT:
             {

jetty-jaas/src/main/java/org/eclipse/jetty/jaas/JAASLoginService.java

@@ -222,7 +222,7 @@ public class JAASLoginService extends AbstractLifeCycle implements LoginService
             }
             else
             {
-                Class<?> clazz = Loader.loadClass(getClass(), _callbackHandlerClass);
+                Class<?> clazz = Loader.loadClass(_callbackHandlerClass);
                 callbackHandler = (CallbackHandler)clazz.newInstance();
             }
             //set up the login context

jetty-jaas/src/main/java/org/eclipse/jetty/jaas/spi/JDBCLoginModule.java

@@ -103,7 +103,7 @@ public class JDBCLoginModule extends AbstractDatabaseLoginModule
                 dbPassword = "";
 
             if (dbDriver != null)
-                Loader.loadClass(this.getClass(), dbDriver).newInstance();
+                Loader.loadClass(dbDriver).newInstance();
         }
         catch (ClassNotFoundException e)
         {

jetty-jmx/src/main/java/org/eclipse/jetty/jmx/ObjectMBean.java

@@ -130,7 +130,20 @@ public class ObjectMBean implements DynamicMBean
 
                 try
                 { 
-                    Class<?> mClass = (Object.class.equals(oClass))?oClass=ObjectMBean.class:Loader.loadClass(oClass,mName);
+                    Class<?> mClass;
+                    try
+                    {
+                        // Look for an MBean class from the same loader that loaded the original class
+                        mClass = (Object.class.equals(oClass))?oClass=ObjectMBean.class:Loader.loadClass(oClass,mName);
+                    }
+                    catch (ClassNotFoundException e)
+                    {
+                        // Not found, so if not the same as the thread context loader, try that.
+                        if (Thread.currentThread().getContextClassLoader()==oClass.getClassLoader())
+                            throw e;
+                        LOG.ignore(e);
+                        mClass=Loader.loadClass(oClass,mName);
+                    }
 
                     if (LOG.isDebugEnabled())
                         LOG.debug("ObjectMbean: mbeanFor {} mClass={}", o, mClass);

jetty-plus/src/main/java/org/eclipse/jetty/plus/annotation/ContainerInitializer.java

@@ -127,7 +127,7 @@ public class ContainerInitializer
             try
             {
                 for (String s : _applicableTypeNames)
-                    classes.add(Loader.loadClass(context.getClass(), s));
+                    classes.add(Loader.loadClass(s));
 
                 context.getServletContext().setExtendedListenerTypes(true);
                 if (LOG.isDebugEnabled())

jetty-plus/src/main/java/org/eclipse/jetty/plus/annotation/LifeCycleCallback.java

@@ -106,7 +106,7 @@ public abstract class LifeCycleCallback
         if (_target == null)
         {
             if (_targetClass == null)
-                _targetClass = Loader.loadClass(null, _className);
+                _targetClass = Loader.loadClass(_className);
             _target = _targetClass.getDeclaredMethod(_methodName, TypeUtil.NO_ARGS);
         }
 

jetty-plus/src/main/java/org/eclipse/jetty/plus/webapp/EnvConfiguration.java

@@ -41,6 +41,7 @@ import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
 import org.eclipse.jetty.webapp.AbstractConfiguration;
 import org.eclipse.jetty.webapp.Configuration;
+import org.eclipse.jetty.webapp.WebAppClassLoader;
 import org.eclipse.jetty.webapp.WebAppContext;
 import org.eclipse.jetty.xml.XmlConfiguration;
 
@@ -113,7 +114,7 @@ public class EnvConfiguration extends AbstractConfiguration
                 {
                     localContextRoot.getRoot().addListener(listener);
                     XmlConfiguration configuration = new XmlConfiguration(jettyEnvXmlUrl);
-                    configuration.configure(context);
+                    WebAppClassLoader.runWithServerClassAccess(()->{configuration.configure(context);return null;});
                 }
                 finally
                 {

jetty-security/src/main/java/org/eclipse/jetty/security/JDBCLoginService.java

@@ -164,7 +164,7 @@ public class JDBCLoginService extends MappedLoginService
                    + " = u."
                    + _userRoleTableRoleKey;
         
-        Loader.loadClass(this.getClass(), _jdbcDriver).newInstance();
+        Loader.loadClass(_jdbcDriver).newInstance();
         super.doStart();
     }
 

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

@@ -1673,7 +1673,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             return null;
 
         if (_classLoader == null)
-            return Loader.loadClass(this.getClass(),className);
+            return Loader.loadClass(className);
 
         return _classLoader.loadClass(className);
     }
@@ -2317,7 +2317,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             try
             {
                 @SuppressWarnings({ "unchecked", "rawtypes" })
-                Class<? extends EventListener> clazz = _classLoader==null?Loader.loadClass(ContextHandler.class,className):(Class)_classLoader.loadClass(className);
+                Class<? extends EventListener> clazz = _classLoader==null?Loader.loadClass(className):(Class)_classLoader.loadClass(className);
                 addListener(clazz);
             }
             catch (ClassNotFoundException e)
@@ -2410,7 +2410,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
                 //classloader, or a parent of it
                 try
                 {
-                    Class<?> reflect = Loader.loadClass(getClass(), "sun.reflect.Reflection");
+                    Class<?> reflect = Loader.loadClass("sun.reflect.Reflection");
                     Method getCallerClass = reflect.getMethod("getCallerClass", Integer.TYPE);
                     Class<?> caller = (Class<?>)getCallerClass.invoke(null, 2);
 

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

@@ -92,7 +92,7 @@ public abstract class BaseHolder<T> extends AbstractLifeCycle implements Dumpabl
         {
             try
             {
-                _class=Loader.loadClass(Holder.class, _className);
+                _class=Loader.loadClass(_className);
                 if(LOG.isDebugEnabled())
                     LOG.debug("Holding {} from {}",_class,_class.getClassLoader());
             }

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

@@ -421,7 +421,7 @@ public class ServletContextHandler extends ContextHandler
      */
     public ServletHolder addServlet(Class<? extends Servlet> servlet,String pathSpec)
     {
-        return getServletHandler().addServletWithMapping(servlet.getName(), pathSpec);
+        return getServletHandler().addServletWithMapping(servlet,pathSpec);
     }
 
     /* ------------------------------------------------------------ */

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

@@ -875,7 +875,7 @@ public class ServletHolder extends Holder<Servlet> implements UserIdentity.Scope
             try
             {
                 //check for apache
-                Loader.loadClass(Holder.class, APACHE_SENTINEL_CLASS);
+                Loader.loadClass(APACHE_SENTINEL_CLASS);
                 if (LOG.isDebugEnabled())LOG.debug("Apache jasper detected");
                 _jspContainer = JspContainer.APACHE;
             }
@@ -897,7 +897,7 @@ public class ServletHolder extends Holder<Servlet> implements UserIdentity.Scope
         jsp = jsp.substring(i);
         try
         {
-            Class<?> jspUtil = Loader.loadClass(Holder.class, "org.apache.jasper.compiler.JspUtil");
+            Class<?> jspUtil = Loader.loadClass("org.apache.jasper.compiler.JspUtil");
             Method makeJavaIdentifier = jspUtil.getMethod("makeJavaIdentifier", String.class);
             return (String)makeJavaIdentifier.invoke(null, jsp);
         }
@@ -923,7 +923,7 @@ public class ServletHolder extends Holder<Servlet> implements UserIdentity.Scope
             return "";
         try
         {
-            Class<?> jspUtil = Loader.loadClass(Holder.class, "org.apache.jasper.compiler.JspUtil");
+            Class<?> jspUtil = Loader.loadClass("org.apache.jasper.compiler.JspUtil");
             Method makeJavaPackage = jspUtil.getMethod("makeJavaPackage", String.class);
             return (String)makeJavaPackage.invoke(null, jsp.substring(0,i));
         }

jetty-servlet/src/main/java/org/eclipse/jetty/servlet/listener/ELContextCleaner.java

@@ -52,7 +52,7 @@ public class ELContextCleaner implements ServletContextListener
         try
         {
             //Check that the BeanELResolver class is on the classpath
-            Class<?> beanELResolver = Loader.loadClass(this.getClass(), "javax.el.BeanELResolver");
+            Class<?> beanELResolver = Loader.loadClass("javax.el.BeanELResolver");
 
             //Get a reference via reflection to the properties field which is holding class references
             Field field = getField(beanELResolver);

jetty-util-ajax/src/main/java/org/eclipse/jetty/util/ajax/JSON.java

@@ -935,7 +935,7 @@ public class JSON
         {
             try
             {
-                Class c = Loader.loadClass(JSON.class,classname);
+                Class c = Loader.loadClass(classname);
                 return convertTo(c,map);
             }
             catch (ClassNotFoundException e)

jetty-util-ajax/src/main/java/org/eclipse/jetty/util/ajax/JSONCollectionConvertor.java

@@ -36,7 +36,7 @@ public class JSONCollectionConvertor implements JSON.Convertor
     {
         try
         {
-            Collection result = (Collection)Loader.loadClass(getClass(), (String)object.get("class")).newInstance();
+            Collection result = (Collection)Loader.loadClass((String)object.get("class")).newInstance();
             Collections.addAll(result, (Object[])object.get("list"));
             return result;
         }

jetty-util-ajax/src/main/java/org/eclipse/jetty/util/ajax/JSONEnumConvertor.java

@@ -43,7 +43,7 @@ public class JSONEnumConvertor implements JSON.Convertor
     {
         try
         {
-            Class<?> e = Loader.loadClass(getClass(),"java.lang.Enum");
+            Class<?> e = Loader.loadClass("java.lang.Enum");
             _valueOf=e.getMethod("valueOf",Class.class,String.class);
         }
         catch(Exception e)
@@ -68,7 +68,7 @@ public class JSONEnumConvertor implements JSON.Convertor
             throw new UnsupportedOperationException();
         try
         {
-            Class c=Loader.loadClass(getClass(),(String)map.get("class"));
+            Class c=Loader.loadClass((String)map.get("class"));
             return _valueOf.invoke(null,c,map.get("value"));
         }
         catch(Exception e)

jetty-util-ajax/src/main/java/org/eclipse/jetty/util/ajax/JSONPojoConvertorFactory.java

@@ -65,7 +65,7 @@ public class JSONPojoConvertorFactory implements JSON.Convertor
         {
             try
             {
-                Class cls=Loader.loadClass(JSON.class,clsName);
+                Class cls=Loader.loadClass(clsName);
                 convertor=new JSONPojoConvertor(cls,_fromJson);
                 _json.addConvertorFor(clsName, convertor);
              }
@@ -91,7 +91,7 @@ public class JSONPojoConvertorFactory implements JSON.Convertor
             {
                 try
                 {
-                    Class cls=Loader.loadClass(JSON.class,clsName);
+                    Class cls=Loader.loadClass(clsName);
                     convertor=new JSONPojoConvertor(cls,_fromJson);
                     _json.addConvertorFor(clsName, convertor);
                 }

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

@@ -46,107 +46,55 @@ import org.eclipse.jetty.util.resource.Resource;
 public class Loader
 {
     /* ------------------------------------------------------------ */
-    public static URL getResource(Class<?> loadClass,String name)
+    public static URL getResource(String name)
     {
-        URL url =null;
+        ClassLoader loader=Thread.currentThread().getContextClassLoader();
-        ClassLoader context_loader=Thread.currentThread().getContextClassLoader();
+        return loader==null?ClassLoader.getSystemResource(name):loader.getResource(name); 
-        if (context_loader!=null)
-            url=context_loader.getResource(name); 
-        
-        if (url==null && loadClass!=null)
-        {
-            ClassLoader load_loader=loadClass.getClassLoader();
-            if (load_loader!=null && load_loader!=context_loader)
-                url=load_loader.getResource(name);
-        }
-
-        if (url==null)
-            url=ClassLoader.getSystemResource(name);
-
-        return url;
     }
 
     /* ------------------------------------------------------------ */
     /** Load a class.
+     * <p>Load a class either from the thread context classloader or if none, the system
+     * loader</p>
+     * @param name the name of the new class to load
      * 
-     * @param loadClass the class to use for the ClassLoader that was used
-     * @param name the name of the new class to load, using the same ClassLoader as the <code>loadClass</code> 
      * @return Class
      * @throws ClassNotFoundException if not able to find the class
      */
     @SuppressWarnings("rawtypes")
-    public static Class loadClass(Class loadClass,String name)
+    public static Class loadClass(String name)
         throws ClassNotFoundException
     {
-        ClassNotFoundException ex=null;
+        ClassLoader loader=Thread.currentThread().getContextClassLoader();
-        Class<?> c =null;
+        return (loader==null ) ? Class.forName(name) : loader.loadClass(name);
-        ClassLoader context_loader=Thread.currentThread().getContextClassLoader();
-        if (context_loader!=null )
-        {
-            try { c=context_loader.loadClass(name); }
-            catch (ClassNotFoundException e) {ex=e;}
     } 
 
-        if (c==null && loadClass!=null)
+    /* ------------------------------------------------------------ */
+    /** Load a class.
+     * Load a class from the same classloader as the passed  <code>loadClass</code>, or if none
+     * then use {@link #loadClass(String)}
+     * 
+     * @return Class
+     * @throws ClassNotFoundException if not able to find the class
+     */
+    @SuppressWarnings("rawtypes")
+    public static Class loadClass(Class loaderClass, String name)
+        throws ClassNotFoundException
     {
-            ClassLoader load_loader=loadClass.getClassLoader();
+        if (loaderClass!=null && loaderClass.getClassLoader()!=null)
-            if (load_loader!=null && load_loader!=context_loader)
+            return loaderClass.getClassLoader().loadClass(name);
-            {
+        return loadClass(name);
-                try { c=load_loader.loadClass(name); }
-                catch (ClassNotFoundException e) {if(ex==null)ex=e;}
     }
-        }
-
-        if (c==null)
-        {
-            try { c=Class.forName(name); }
-            catch (ClassNotFoundException e) 
-            {
-                if(ex!=null)
-                    throw ex;
-                throw e;
-            }
-        }   
-
-        return c;
-    }
-    
     
     
     /* ------------------------------------------------------------ */
-    public static ResourceBundle getResourceBundle(Class<?> loadClass,String name,boolean checkParents, Locale locale)
+    public static ResourceBundle getResourceBundle(String name,boolean checkParents,Locale locale)
         throws MissingResourceException
     {
-        MissingResourceException ex=null;
-        ResourceBundle bundle =null;
         ClassLoader loader=Thread.currentThread().getContextClassLoader();
-        while (bundle==null && loader!=null )
+        return loader==null ? ResourceBundle.getBundle(name, locale) : ResourceBundle.getBundle(name, locale, loader);
-        {
-            try { bundle=ResourceBundle.getBundle(name, locale, loader); }
-            catch (MissingResourceException e) {if(ex==null)ex=e;}
-            loader=(bundle==null&&checkParents)?loader.getParent():null;
     }
     
-        loader=loadClass==null?null:loadClass.getClassLoader();
-        while (bundle==null && loader!=null )
-        {
-            try { bundle=ResourceBundle.getBundle(name, locale, loader); }
-            catch (MissingResourceException e) {if(ex==null)ex=e;}
-            loader=(bundle==null&&checkParents)?loader.getParent():null;
-        }       
-
-        if (bundle==null)
-        {
-            try { bundle=ResourceBundle.getBundle(name, locale); }
-            catch (MissingResourceException e) {if(ex==null)ex=e;}
-        }   
-
-        if (bundle!=null)
-            return bundle;
-        throw ex;
-    }
-    
-    
     /* ------------------------------------------------------------ */
     /**
      * Generate the classpath (as a string) of all classloaders

jetty-util/src/main/java/org/eclipse/jetty/util/log/JavaUtilLog.java

@@ -95,7 +95,7 @@ public class JavaUtilLog extends AbstractLogger
                         {
                             try
                             {
-                                URL props = Loader.getResource(JavaUtilLog.class,properties);
+                                URL props = Loader.getResource(properties);
                                 if (props != null)
                                     LogManager.getLogManager().readConfiguration(props.openStream());
                             }

jetty-util/src/main/java/org/eclipse/jetty/util/log/Log.java

@@ -132,7 +132,7 @@ public class Log
     
     static void loadProperties(String resourceName, Properties props)
     {
-        URL testProps = Loader.getResource(Log.class,resourceName);
+        URL testProps = Loader.getResource(resourceName);
         if (testProps != null)
         {
             try (InputStream in = testProps.openStream())
@@ -169,7 +169,7 @@ public class Log
 
             try
             {
-                Class<?> log_class = __logClass==null?null:Loader.loadClass(Log.class, __logClass);
+                Class<?> log_class = __logClass==null?null:Loader.loadClass(__logClass);
                 if (LOG == null || (log_class!=null && !LOG.getClass().equals(log_class)))
                 {
                     LOG = (Logger)log_class.newInstance();

jetty-util/src/main/java/org/eclipse/jetty/util/resource/Resource.java

@@ -269,7 +269,7 @@ public abstract class Resource implements ResourceFactory, Closeable
     /* ------------------------------------------------------------ */
     /** Find a classpath resource.
      * The {@link java.lang.Class#getResource(String)} method is used to lookup the resource. If it is not
-     * found, then the {@link Loader#getResource(Class, String)} method is used.
+     * found, then the {@link Loader#getResource(String)} method is used.
      * If it is still not found, then {@link ClassLoader#getSystemResource(String)} is used.
      * Unlike {@link ClassLoader#getSystemResource(String)} this method does not check for normal resources.
      * @param name The relative name of the resource
@@ -283,7 +283,7 @@ public abstract class Resource implements ResourceFactory, Closeable
         URL url=Resource.class.getResource(name);
         
         if (url==null)
-            url=Loader.getResource(Resource.class,name);
+            url=Loader.getResource(name);
         if (url==null)
             return null;
         return newResource(url,useCaches);

jetty-util/src/main/java/org/eclipse/jetty/util/thread/ExecutionStrategy.java

@@ -83,7 +83,7 @@ public interface ExecutionStrategy
             {
                 try
                 {
-                    Class<? extends ExecutionStrategy> c = Loader.loadClass(producer.getClass(),strategy);
+                    Class<? extends ExecutionStrategy> c = Loader.loadClass(strategy);
                     Constructor<? extends ExecutionStrategy> m = c.getConstructor(Producer.class,Executor.class);
                     LOG.info("Use {} for {}",c.getSimpleName(),producer.getClass().getName());
                     return  m.newInstance(producer,executor);

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

@@ -79,7 +79,7 @@ public abstract class DiscoveredAnnotation
         
         try
         {
-            _clazz = Loader.loadClass(null, _className);
+            _clazz = Loader.loadClass(_className);
         }
         catch (Exception e)
         {

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

@@ -90,7 +90,7 @@ public class JettyWebXmlConfiguration extends AbstractConfiguration
 
                     if (jetty_config==null)
                     {
-                        jetty_config=new XmlConfiguration(jetty.getURL());
+                        jetty_config=new XmlConfiguration(jetty.getURI().toURL());
                     }
                     else
                     {
@@ -99,7 +99,8 @@ public class JettyWebXmlConfiguration extends AbstractConfiguration
                     setupXmlConfiguration(jetty_config, web_inf);
                     try
                     {
-                        jetty_config.configure(context);
+                        XmlConfiguration config=jetty_config;
+                        WebAppClassLoader.runWithServerClassAccess(()->{config.configure(context);return null;});
                     }
                     catch (ClassNotFoundException e)
                     {
@@ -125,6 +126,6 @@ public class JettyWebXmlConfiguration extends AbstractConfiguration
     {
         Map<String,String> props = jetty_config.getProperties();
         // TODO - should this be an id rather than a property?
-        props.put(PROPERTY_THIS_WEB_INF_URL, String.valueOf(web_inf.getURL()));
+        props.put(PROPERTY_THIS_WEB_INF_URL, String.valueOf(web_inf.getURI()));
     }
 }

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

@@ -273,7 +273,7 @@ public class StandardDescriptorProcessor extends IterativeDescriptorProcessor
         {
             try
             {
-                Loader.loadClass(this.getClass(), servlet_class);
+                Loader.loadClass(servlet_class);
             }
             catch (ClassNotFoundException e)
             {

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

@@ -27,6 +27,7 @@ import java.net.URL;
 import java.net.URLClassLoader;
 import java.security.CodeSource;
 import java.security.PermissionCollection;
+import java.security.PrivilegedExceptionAction;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
@@ -35,6 +36,7 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import java.util.StringTokenizer;
+import java.util.concurrent.Callable;
 import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.eclipse.jetty.util.IO;
@@ -71,6 +73,7 @@ public class WebAppClassLoader extends URLClassLoader
     }
 
     private static final Logger LOG = Log.getLogger(WebAppClassLoader.class);
+    private static final ThreadLocal<Boolean> __loadServerClasses = new ThreadLocal<>();
     
     private final Context _context;
     private final ClassLoader _parent;
@@ -78,6 +81,7 @@ public class WebAppClassLoader extends URLClassLoader
     private String _name=String.valueOf(hashCode());
     private final List<ClassFileTransformer> _transformers = new CopyOnWriteArrayList<>();
     
+    
     /* ------------------------------------------------------------ */
     /** The Context in which the classloader operates.
      */
@@ -134,6 +138,31 @@ public class WebAppClassLoader extends URLClassLoader
         
     }
 
+    /* ------------------------------------------------------------ */
+    /** Run an action with access to ServerClasses
+     * <p>Run the passed {@link PrivilegedExceptionAction} with the classloader
+     * configured so as to allow server classes to be visible</p>
+     * @param action The action to run
+     * @return The return from the action
+     * @throws Exception
+     */
+    public static <T> T runWithServerClassAccess(PrivilegedExceptionAction<T> action) throws Exception
+    {
+        Boolean lsc=__loadServerClasses.get();
+        try
+        {
+            __loadServerClasses.set(true);
+            return action.run();
+        }
+        finally
+        {
+            if (lsc==null)
+                __loadServerClasses.remove();
+            else
+                __loadServerClasses.set(lsc);
+        }
+    }
+    
     /* ------------------------------------------------------------ */
     /** 
      * Constructor.
@@ -333,7 +362,7 @@ public class WebAppClassLoader extends URLClassLoader
     public Enumeration<URL> getResources(String name) throws IOException
     {
         boolean system_class=_context.isSystemClass(name);
-        boolean server_class=_context.isServerClass(name);
+        boolean server_class=_context.isServerClass(name) && !Boolean.TRUE.equals(__loadServerClasses.get());
         
         List<URL> from_parent = toList(server_class?null:_parent.getResources(name));
         List<URL> from_webapp = toList((system_class&&!from_parent.isEmpty())?null:this.findResources(name));
@@ -376,7 +405,7 @@ public class WebAppClassLoader extends URLClassLoader
             tmp = tmp.substring(0, tmp.length()-6);
         
         boolean system_class=_context.isSystemClass(tmp);
-        boolean server_class=_context.isServerClass(tmp);
+        boolean server_class=_context.isServerClass(tmp) && !Boolean.TRUE.equals(__loadServerClasses.get());
         
         if (LOG.isDebugEnabled())
             LOG.debug("getResource({}) system={} server={} cl={}",name,system_class,server_class,this);
@@ -439,7 +468,7 @@ public class WebAppClassLoader extends URLClassLoader
             boolean tried_parent= false;
 
             boolean system_class=_context.isSystemClass(name);
-            boolean server_class=_context.isServerClass(name);
+            boolean server_class=_context.isServerClass(name) && !Boolean.TRUE.equals(__loadServerClasses.get());
 
             if (LOG.isDebugEnabled())
                 LOG.debug("loadClass({}) system={} server={} cl={}",name,system_class,server_class,this);

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

@@ -144,6 +144,7 @@ public class WebAppContext extends ServletContextHandler implements WebAppClassL
         "-org.eclipse.jetty.jaas.",         // don't hide jaas classes
         "-org.eclipse.jetty.servlets.",     // don't hide jetty servlets
         "-org.eclipse.jetty.servlet.DefaultServlet", // don't hide default servlet
+        "-org.eclipse.jetty.servlet.NoJspServlet", // don't hide noJspServlet servlet
         "-org.eclipse.jetty.jsp.",          //don't hide jsp servlet
         "-org.eclipse.jetty.servlet.listener.", // don't hide useful listeners
         "-org.eclipse.jetty.websocket.",    // don't hide websocket classes from webapps (allow webapp to use ones from system classloader)
@@ -924,7 +925,7 @@ public class WebAppContext extends ServletContextHandler implements WebAppClassL
         if (_configurationClasses.size()==0)
             _configurationClasses.addAll(Configuration.ClassList.serverDefault(getServer()));
         for (String configClass : _configurationClasses)
-            _configurations.add((Configuration)Loader.loadClass(this.getClass(), configClass).newInstance());
+            _configurations.add((Configuration)Loader.loadClass(configClass).newInstance());
     }
 
     /* ------------------------------------------------------------ */

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

@@ -23,8 +23,6 @@ import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 
-import javax.servlet.Servlet;
-
 import org.eclipse.jetty.util.Loader;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
@@ -89,31 +87,31 @@ public class WebDescriptor extends Descriptor
             void mapResources()
             {
                 //set up cache of DTDs and schemas locally
-                URL dtd22=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_2_2.dtd");
+                URL dtd22=Loader.getResource("javax/servlet/resources/web-app_2_2.dtd");
-                URL dtd23=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_2_3.dtd");
+                URL dtd23=Loader.getResource("javax/servlet/resources/web-app_2_3.dtd");
-                URL j2ee14xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/j2ee_1_4.xsd");
+                URL j2ee14xsd=Loader.getResource("javax/servlet/resources/j2ee_1_4.xsd");
-                URL javaee5=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_5.xsd");
+                URL javaee5=Loader.getResource("javax/servlet/resources/javaee_5.xsd");
-                URL javaee6=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_6.xsd");
+                URL javaee6=Loader.getResource("javax/servlet/resources/javaee_6.xsd");
-                URL javaee7=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_7.xsd");
+                URL javaee7=Loader.getResource("javax/servlet/resources/javaee_7.xsd");
 
-                URL webapp24xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_2_4.xsd");
+                URL webapp24xsd=Loader.getResource("javax/servlet/resources/web-app_2_4.xsd");
-                URL webapp25xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_2_5.xsd");
+                URL webapp25xsd=Loader.getResource("javax/servlet/resources/web-app_2_5.xsd");
-                URL webapp30xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_3_0.xsd");
+                URL webapp30xsd=Loader.getResource("javax/servlet/resources/web-app_3_0.xsd");
-                URL webapp31xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-app_3_1.xsd");
+                URL webapp31xsd=Loader.getResource("javax/servlet/resources/web-app_3_1.xsd");
                 
-                URL webcommon30xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-common_3_0.xsd");
+                URL webcommon30xsd=Loader.getResource("javax/servlet/resources/web-common_3_0.xsd");
-                URL webcommon31xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-common_3_1.xsd");
+                URL webcommon31xsd=Loader.getResource("javax/servlet/resources/web-common_3_1.xsd");
             
-                URL webfragment30xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-fragment_3_0.xsd");
+                URL webfragment30xsd=Loader.getResource("javax/servlet/resources/web-fragment_3_0.xsd");
-                URL webfragment31xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/web-fragment_3_1.xsd");
+                URL webfragment31xsd=Loader.getResource("javax/servlet/resources/web-fragment_3_1.xsd");
                 
-                URL schemadtd=Loader.getResource(Servlet.class,"javax/servlet/resources/XMLSchema.dtd");
+                URL schemadtd=Loader.getResource("javax/servlet/resources/XMLSchema.dtd");
-                URL xmlxsd=Loader.getResource(Servlet.class,"javax/servlet/resources/xml.xsd");
+                URL xmlxsd=Loader.getResource("javax/servlet/resources/xml.xsd");
-                URL webservice11xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/j2ee_web_services_client_1_1.xsd");
+                URL webservice11xsd=Loader.getResource("javax/servlet/resources/j2ee_web_services_client_1_1.xsd");
-                URL webservice12xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_web_services_client_1_2.xsd");
+                URL webservice12xsd=Loader.getResource("javax/servlet/resources/javaee_web_services_client_1_2.xsd");
-                URL webservice13xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_web_services_client_1_3.xsd");
+                URL webservice13xsd=Loader.getResource("javax/servlet/resources/javaee_web_services_client_1_3.xsd");
-                URL webservice14xsd=Loader.getResource(Servlet.class,"javax/servlet/resources/javaee_web_services_client_1_4.xsd");
+                URL webservice14xsd=Loader.getResource("javax/servlet/resources/javaee_web_services_client_1_4.xsd");
-                URL datatypesdtd=Loader.getResource(Servlet.class,"javax/servlet/resources/datatypes.dtd");
+                URL datatypesdtd=Loader.getResource("javax/servlet/resources/datatypes.dtd");
                 
                 URL jsp20xsd = null;
                 URL jsp21xsd = null;
@@ -123,10 +121,10 @@ public class WebDescriptor extends Descriptor
                 try
                 {
                     //try both javax/servlet/resources and javax/servlet/jsp/resources to load 
-                    jsp20xsd = Loader.getResource(Servlet.class, "javax/servlet/resources/jsp_2_0.xsd");
+                    jsp20xsd = Loader.getResource("javax/servlet/resources/jsp_2_0.xsd");
-                    jsp21xsd = Loader.getResource(Servlet.class, "javax/servlet/resources/jsp_2_1.xsd");
+                    jsp21xsd = Loader.getResource("javax/servlet/resources/jsp_2_1.xsd");
-                    jsp22xsd = Loader.getResource(Servlet.class, "javax/servlet/resources/jsp_2_2.xsd");
+                    jsp22xsd = Loader.getResource("javax/servlet/resources/jsp_2_2.xsd");
-                    jsp23xsd = Loader.getResource(Servlet.class, "javax/servlet/resources/jsp_2_3.xsd");
+                    jsp23xsd = Loader.getResource("javax/servlet/resources/jsp_2_3.xsd");
                 }
                 catch (Exception e)
                 {
@@ -134,10 +132,10 @@ public class WebDescriptor extends Descriptor
                 }
                 finally
                 {
-                    if (jsp20xsd == null) jsp20xsd = Loader.getResource(Servlet.class, "javax/servlet/jsp/resources/jsp_2_0.xsd");
+                    if (jsp20xsd == null) jsp20xsd = Loader.getResource("javax/servlet/jsp/resources/jsp_2_0.xsd");
-                    if (jsp21xsd == null) jsp21xsd = Loader.getResource(Servlet.class, "javax/servlet/jsp/resources/jsp_2_1.xsd");
+                    if (jsp21xsd == null) jsp21xsd = Loader.getResource("javax/servlet/jsp/resources/jsp_2_1.xsd");
-                    if (jsp22xsd == null) jsp22xsd = Loader.getResource(Servlet.class, "javax/servlet/jsp/resources/jsp_2_2.xsd");
+                    if (jsp22xsd == null) jsp22xsd = Loader.getResource("javax/servlet/jsp/resources/jsp_2_2.xsd");
-                    if (jsp23xsd == null) jsp23xsd = Loader.getResource(Servlet.class, "javax/servlet/jsp/resources/jsp_2_3.xsd");
+                    if (jsp23xsd == null) jsp23xsd = Loader.getResource("javax/servlet/jsp/resources/jsp_2_3.xsd");
                 }
                 
                 redirectEntity("web-app_2_2.dtd",dtd22);

jetty-websocket/websocket-server/src/test/java/org/eclipse/jetty/websocket/server/browser/BrowserSocket.java

@@ -136,7 +136,7 @@ public class BrowserSocket
         if (message.charAt(0) == '@')
         {
             String name = message.substring(1);
-            URL url = Loader.getResource(BrowserSocket.class,name);
+            URL url = Loader.getResource(name);
             if (url == null)
             {
                 writeMessage("Unable to find resource: " + name);

jetty-xml/src/main/java/org/eclipse/jetty/xml/XmlConfiguration.java

@@ -90,10 +90,10 @@ public class XmlConfiguration
     private static XmlParser initParser()
     {
         XmlParser parser = new XmlParser();
-        URL config60 = Loader.getResource(XmlConfiguration.class, "org/eclipse/jetty/xml/configure_6_0.dtd");
+        URL config60 = Loader.getResource("org/eclipse/jetty/xml/configure_6_0.dtd");
-        URL config76 = Loader.getResource(XmlConfiguration.class,"org/eclipse/jetty/xml/configure_7_6.dtd");
+        URL config76 = Loader.getResource("org/eclipse/jetty/xml/configure_7_6.dtd");
-        URL config90 = Loader.getResource(XmlConfiguration.class,"org/eclipse/jetty/xml/configure_9_0.dtd");
+        URL config90 = Loader.getResource("org/eclipse/jetty/xml/configure_9_0.dtd");
-        URL config93 = Loader.getResource(XmlConfiguration.class,"org/eclipse/jetty/xml/configure_9_3.dtd");
+        URL config93 = Loader.getResource("org/eclipse/jetty/xml/configure_9_3.dtd");
         parser.redirectEntity("configure.dtd",config90);
         parser.redirectEntity("configure_1_0.dtd",config60);
         parser.redirectEntity("configure_1_1.dtd",config60);
@@ -365,7 +365,7 @@ public class XmlConfiguration
             if (className == null)
                 return null;
 
-            return Loader.loadClass(XmlConfiguration.class,className);
+            return Loader.loadClass(className);
         }
 
         /**
@@ -708,7 +708,7 @@ public class XmlConfiguration
             if (clazz!=null)
             {
                 // static call
-                oClass=Loader.loadClass(XmlConfiguration.class,clazz);
+                oClass=Loader.loadClass(clazz);
                 obj=null;
             }
             else if (obj!=null)
@@ -755,7 +755,7 @@ public class XmlConfiguration
             if (LOG.isDebugEnabled())
                 LOG.debug("XML new " + clazz);
             
-            Class<?> oClass = Loader.loadClass(XmlConfiguration.class,clazz);
+            Class<?> oClass = Loader.loadClass(clazz);
             
             // Find the <Arg> elements
             Map<String, Object> namedArgMap = new HashMap<>();
@@ -846,7 +846,7 @@ public class XmlConfiguration
                             aClass = InetAddress.class;
                             break;
                         default:
-                            aClass = Loader.loadClass(XmlConfiguration.class, type);
+                            aClass = Loader.loadClass(type);
                             break;
                     }
                 }

tests/test-loginservice/src/test/java/org/eclipse/jetty/DataSourceLoginServiceTest.java

@@ -172,7 +172,7 @@ public class DataSourceLoginServiceTest
      
      protected void changePassword (String user, String newpwd) throws Exception
      {
-         Loader.loadClass(this.getClass(), "org.apache.derby.jdbc.EmbeddedDriver").newInstance();
+         Loader.loadClass("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
          try (Connection connection = DriverManager.getConnection(DatabaseLoginServiceTestServer.__dbURL, "", "");
               Statement stmt = connection.createStatement())
          {

tests/test-loginservice/src/test/java/org/eclipse/jetty/DatabaseLoginServiceTestServer.java

@@ -92,7 +92,7 @@ public class DatabaseLoginServiceTestServer
         //System.err.println("Running script:"+scriptFile.getAbsolutePath());
         try (FileInputStream fileStream = new FileInputStream(scriptFile))
         {
-            Loader.loadClass(fileStream.getClass(), "org.apache.derby.jdbc.EmbeddedDriver").newInstance();
+            Loader.loadClass("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
             Connection connection = DriverManager.getConnection(__dbURL, "", "");
             ByteArrayOutputStream out = new ByteArrayOutputStream();
             return ij.runScript(connection, fileStream, "UTF-8", out, "UTF-8");

tests/test-sessions/test-sessions-common/src/main/java/org/eclipse/jetty/server/session/AbstractSessionRenewTest.java

@@ -52,6 +52,7 @@ public abstract class AbstractSessionRenewTest
         int scavengePeriod = 3;
         AbstractTestServer server = createServer(0, 1, scavengePeriod);
         WebAppContext context = server.addWebAppContext(".", contextPath);
+        context.setParentLoaderPriority(true);
         context.addServlet(TestServlet.class, servletMapping);
         TestHttpSessionIdListener testListener = new TestHttpSessionIdListener();
         context.addEventListener(testListener);