client Connection refused by jetty server-version11.0.0 - jetty

Question

MainClass
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.websocket.server.config.JettyWebSocketServletContainerInitializer;
public class WebSocketServer {
private Server server;
public void setup() {
server = new Server();
ServerConnector connector = new ServerConnector(server);
connector.setPort(12345);
server.addConnector(connector);
ServletContextHandler contextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);
contextHandler.setContextPath("/");
contextHandler.addServlet(WebSocketServlet.class, "/websocket");
JettyWebSocketServletContainerInitializer.configure(contextHandler, null);
server.setHandler(contextHandler);
}
public void start() throws Exception {
server.start();
server.dump(System.err);
server.join();
}
public static void main(String args[]) throws Exception {
WebSocketServer webSocketServer = new WebSocketServer();
webSocketServer.setup();
webSocketServer.start();
}
}
JettyWebsocketServelet Implementation:
public class WebSocketServlet extends JettyWebSocketServlet {
#Override
protected void configure(JettyWebSocketServletFactory factory) {
// TODO Auto-generated method stub
factory.register(WebSocketServer.class);
}
}
Dependency:
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>websocket-jetty-server</artifactId>
<version>11.0.2</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-server</artifactId>
<version>11.0.2</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-http</artifactId>
<version>11.0.2</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlets</artifactId>
<version>11.0.0</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>websocket-jetty-client</artifactId>
<version>11.0.0</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-annotations</artifactId>
<version>11.0.0.beta3</version>
</dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-util</artifactId>
<version>11.0.2</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-io</artifactId>
<version>11.0.2</version>
</dependency>
Error:
java.nio.channels.ClosedChannelException
at org.eclipse.jetty.websocket.core.internal.WebSocketSessionState.onEof(WebSocketSessionState.java:174)
at org.eclipse.jetty.websocket.core.internal.WebSocketCoreSession.onEof(WebSocketCoreSession.java:329)
at org.eclipse.jetty.websocket.core.internal.WebSocketConnection.fillAndParse(WebSocketConnection.java:456)
at org.eclipse.jetty.websocket.core.internal.WebSocketConnection.onFillable(WebSocketConnection.java:314)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:319)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:100)
at org.eclipse.jetty.io.SocketChannelEndPoint$1.run(SocketChannelEndPoint.java:101)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:132)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:894)
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1038)
at java.base/java.lang.Thread.run(Thread.java:834)
Connecting getting refused and getting above error ****JDK version is 11 ****

Answer 1

The error message is the result of two mildly different versions of the same dependency on the classpath.SImply it means that there are multiple or more than one dependency in the classpath.I could not point you an exact solution on this but generally to debug use the JVM with -verbose option then look at the classes that were being loaded when the exception occurs. You should see some surprising information. For instance, having multiple copies of the same dependency and versions you never expected or would have accepted if you knew they were being included.
To resolve this problem with duplicate jars you can use http://maven.apache.org/plugins/maven-dependency-plugin/ combined with https://maven.apache.org/enforcer/maven-enforcer-plugin/.You need to add those jars to a section of your top-level POM.