SockJS 'close' event debugging

MinimalSockJSClient.java

package com.multitudecorp.benchmark.client;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Map;


// This library is available here: https://github.com/TooTallNate/Java-WebSocket

import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

public class MinimalSockJSClient extends WebSocketClient {

	
	public MinimalSockJSClient(URI serverURI) {
		super(serverURI);
	}
	
	@Override
	public void onClose(int arg0, String arg1, boolean arg2) {
		System.out.println("closed!");
	}

	@Override
	public void onError(Exception e) {
		System.out.println("error! " + e);
	}

	@Override
	public void onMessage(String message) {
		System.out.println("message: " + message);
	}

	@Override
	public void onOpen(ServerHandshake arg0) {
		System.out.println("open");
	}
	
	public static void main(String[] args) {
		try {
			MinimalSockJSClient c = new MinimalSockJSClient(new URI("ws://localhost:8080/websocket"));
			c.connect();
			System.out.println("connect fired, waiting.");
			Thread.sleep(6000);
		} catch (URISyntaxException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

}

server.js

var sockjs_lib = require('sockjs'),
	http = require('http');

var httpServer = http.createServer();

var sockjs = sockjs_lib.createServer();

sockjs.installHandlers(httpServer);
httpServer.listen(8080);

sockjs.on("connection", function(socket) {

	socket.on("close", function() {
		console.log(socket.id + " has closed.");
	});

	console.log(socket.id + " has connected.");

	setTimeout(function() {
		socket.close();
	}, 2000);
			
});