[jetty-users] Potential Memory Leak of Websocket Object

[Rhofman478 <rhofman478@xxxxxxxxxxxxxx>]

Hello,

we experience a memory leak with the use of Jetty 9.2.21.v20170120 (we are still supporting Java 7). We are using the @Websocket annotation to declare our socket object:

@WebSocket(maxTextMessageSize = 1500)

public class SocketAnnotated {

    ...

}

The socket object is created in a WebSocketCreator, like this:

private class ShipWebSocketCreator implements WebSocketCreator {

    @Override

    public Object createWebSocket(ServletUpgradeRequest request, ServletUpgradeResponse response) {

        ShipSocketAnnotated shipSocket = new ShipSocketAnnotated(listener, SocketRole.ROLE_SERVER);

        ....

    }

}

 The problem is, that when a connection is established and later closed, the SocketAnnotated object is not gc'ed. It seems that Jetty is internally still holding a reference to it. I have copied the path to the nearest gc root from visualvm to illustrate the problem (a screenshot can be accessed at http://imgur.com/a/cu7am):

this                                          SocketAnnotated

  websocket                                   JettyAnnotatedEventDriver

    incomingHandler                           WebsocketSession

      session                                 WebsocketServerConnection

        _connection                           SslConnection$DecryptedEntpoint

          _decryptedEndPoint                  SslConnection

            _connection                       SslChannelEndPoint

              attachment                      SelectionKeyImpl

                value                         HashMap$Node

                  [0]                         HashMap$Node

                    table                     HashMap

                      tdToKey (JavaFrame)     EPollSelectorImpl

I have also tried this with the latest version of Jetty (9.4.3.v20170317) but the problem still exists (the path the the gc root however looks slightly different).

I would be happy to provide any additional data needed as this is a rather critical problem to us.

Best regards,

rhofman