diff --git a/jetty-websocket/javax-websocket-client/src/main/java/org/eclipse/jetty/websocket/javax/client/JavaxWebSocketClientContainer.java b/jetty-websocket/javax-websocket-client/src/main/java/org/eclipse/jetty/websocket/javax/client/JavaxWebSocketClientContainer.java
index ae5c8465411..e051d723a28 100644
--- a/jetty-websocket/javax-websocket-client/src/main/java/org/eclipse/jetty/websocket/javax/client/JavaxWebSocketClientContainer.java
+++ b/jetty-websocket/javax-websocket-client/src/main/java/org/eclipse/jetty/websocket/javax/client/JavaxWebSocketClientContainer.java
@@ -22,6 +22,7 @@ import java.io.IOException;
 import java.net.URI;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -126,7 +127,7 @@ public class JavaxWebSocketClientContainer extends JavaxWebSocketContainer imple
         JavaxClientUpgradeRequest upgradeRequest = new JavaxClientUpgradeRequest(this, getWebSocketCoreClient(), destURI, configuredEndpoint);
 
         EndpointConfig config = configuredEndpoint.getConfig();
-        if (config != null && config instanceof ClientEndpointConfig)
+        if (config instanceof ClientEndpointConfig)
         {
             ClientEndpointConfig clientEndpointConfig = (ClientEndpointConfig)config;
 
@@ -140,26 +141,35 @@ public class JavaxWebSocketClientContainer extends JavaxWebSocketContainer imple
                 upgradeRequest.setSubProtocols(clientEndpointConfig.getPreferredSubprotocols());
         }
 
+        long timeout = coreClient.getHttpClient().getConnectTimeout();
         try
         {
             Future<Session> sessionFuture = connect(upgradeRequest);
-            long timeout = coreClient.getHttpClient().getConnectTimeout();
             if (timeout>0)
                 return sessionFuture.get(timeout+1000, TimeUnit.MILLISECONDS);
             return sessionFuture.get();
         }
+        catch (ExecutionException e)
+        {
+            var cause = e.getCause();
+            if (cause instanceof RuntimeException)
+                throw (RuntimeException)cause;
+            if (cause instanceof IOException)
+                throw (IOException)cause;
+            throw new IOException(cause);
+        }
         catch (TimeoutException e)
         {
-            throw new IOException("Connection future not completed " + destURI, e);
+            throw new IOException("Connection future timeout " + timeout + " ms for " + destURI, e);
         }
-        catch (Exception e)
+        catch (Throwable e)
         {
             throw new IOException("Unable to connect to " + destURI, e);
         }
     }
 
     @Override
-    public Session connectToServer(final Class<? extends Endpoint> endpointClass, final ClientEndpointConfig config, URI path) throws DeploymentException, IOException
+    public Session connectToServer(final Class<? extends Endpoint> endpointClass, final ClientEndpointConfig config, URI path) throws IOException
     {
         ClientEndpointConfig clientEndpointConfig = config;
         if (clientEndpointConfig == null)
@@ -171,7 +181,7 @@ public class JavaxWebSocketClientContainer extends JavaxWebSocketContainer imple
     }
 
     @Override
-    public Session connectToServer(final Class<?> annotatedEndpointClass, final URI path) throws DeploymentException, IOException
+    public Session connectToServer(final Class<?> annotatedEndpointClass, final URI path) throws IOException
     {
         ConfiguredEndpoint instance = newConfiguredEndpoint(annotatedEndpointClass, new EmptyClientEndpointConfig());
         return connect(instance, path);
@@ -212,11 +222,11 @@ public class JavaxWebSocketClientContainer extends JavaxWebSocketContainer imple
     {
         try
         {
-            return newConfiguredEndpoint(endpointClass.newInstance(), config);
+            return newConfiguredEndpoint(endpointClass.getConstructor().newInstance(), config);
         }
-        catch (DeploymentException | InstantiationException | IllegalAccessException e)
+        catch (Throwable e)
         {
-            throw new InvalidWebSocketException("Unable to instantiate websocket: " + endpointClass.getClass());
+            throw new InvalidWebSocketException("Unable to instantiate websocket: " + endpointClass.getName());
         }
     }
 
diff --git a/jetty-websocket/javax-websocket-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/client/misbehaving/MisbehavingClassTest.java b/jetty-websocket/javax-websocket-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/client/misbehaving/MisbehavingClassTest.java
index 5a577c2c884..acbc3d27145 100644
--- a/jetty-websocket/javax-websocket-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/client/misbehaving/MisbehavingClassTest.java
+++ b/jetty-websocket/javax-websocket-tests/src/test/java/org/eclipse/jetty/websocket/javax/tests/client/misbehaving/MisbehavingClassTest.java
@@ -18,18 +18,17 @@
 
 package org.eclipse.jetty.websocket.javax.tests.client.misbehaving;
 
-import java.io.IOException;
-import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import javax.websocket.ContainerProvider;
 import javax.websocket.WebSocketContainer;
 
 import org.eclipse.jetty.util.log.StacklessLogging;
+import org.eclipse.jetty.websocket.core.CloseException;
 import org.eclipse.jetty.websocket.core.internal.WebSocketCoreSession;
 import org.eclipse.jetty.websocket.javax.tests.CoreServer;
-import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.MatcherAssert.assertThat;
@@ -39,32 +38,21 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public class MisbehavingClassTest
 {
+    private CoreServer server;
 
-    private static CoreServer server;
-
-    @SuppressWarnings("Duplicates")
-    @BeforeAll
-    public static void startServer() throws Exception
+    @BeforeEach
+    public void startServer() throws Exception
     {
         server = new CoreServer(new CoreServer.EchoNegotiator());
-        // Start Server
         server.start();
     }
 
-    @AfterAll
-    public static void stopServer()
+    @AfterEach
+    public void stopServer() throws Exception
     {
-        try
-        {
-            server.stop();
-        }
-        catch (Exception e)
-        {
-            e.printStackTrace(System.err);
-        }
+        server.stop();
     }
 
-    @SuppressWarnings("Duplicates")
     @Test
     public void testEndpointRuntimeOnOpen() throws Exception
     {
@@ -74,9 +62,8 @@ public class MisbehavingClassTest
 
         try (StacklessLogging ignored = new StacklessLogging(WebSocketCoreSession.class))
         {
-            // expecting IOException during onOpen
-            Exception e = assertThrows(IOException.class, () -> container.connectToServer(socket, server.getWsUri()), "Should have failed .connectToServer()");
-            assertThat(e.getCause(), instanceOf(ExecutionException.class));
+            // Expecting CloseException during onOpen().
+            assertThrows(CloseException.class, () -> container.connectToServer(socket, server.getWsUri()), "Should have failed .connectToServer()");
 
             assertThat("Close should have occurred", socket.closeLatch.await(1, TimeUnit.SECONDS), is(true));
 
@@ -85,7 +72,6 @@ public class MisbehavingClassTest
         }
     }
 
-    @SuppressWarnings("Duplicates")
     @Test
     public void testAnnotatedRuntimeOnOpen() throws Exception
     {
@@ -95,9 +81,8 @@ public class MisbehavingClassTest
 
         try (StacklessLogging ignored = new StacklessLogging(WebSocketCoreSession.class))
         {
-            // expecting IOException during onOpen
-            Exception e = assertThrows(IOException.class, () -> container.connectToServer(socket, server.getWsUri()), "Should have failed .connectToServer()");
-            assertThat(e.getCause(), instanceOf(ExecutionException.class));
+            // Expecting CloseException during onOpen().
+            assertThrows(CloseException.class, () -> container.connectToServer(socket, server.getWsUri()), "Should have failed .connectToServer()");
 
             assertThat("Close should have occurred", socket.closeLatch.await(5, TimeUnit.SECONDS), is(true));