18.9 Handling Errors

To designate a method that handles errors in an annotated WebSocket endpoint, decorate it with @OnError:

@ServerEndpoint("/testendpoint")
public class TestEndpoint {
   ...
   @OnError
   public void error(Session session, Throwable t) {
      t.printStackTrace();
      ...
   }
}

This method is invoked when there are connection problems, runtime errors from message handlers, or conversion errors when decoding messages.