How can I change the example so that the server waits for the client to connect?

Question

Java

I'm going through an example with websockets in libgdx. I comment on the part of the code in which the client is created:

public class PingPongSocketExample extends GdxTest {
  @Override
  public void create () {
    // setup a server thread where we wait for incoming connections
    // to the server
    new Thread(new Runnable() {
      @Override
      public void run () {
        ServerSocketHints hints = new ServerSocketHints();
        ServerSocket server = Gdx.net.newServerSocket(Protocol.TCP, "localhost", 9999, hints);
        // wait for the next client connection
        Socket client = server.accept(null);
        // read message and send it back
        try {
          String message = new BufferedReader(new InputStreamReader(client.getInputStream())).readLine();
          Gdx.app.log("PingPongSocketExample", "got client message: " + message);
          client.getOutputStream().write("PONG\n".getBytes());
        } catch (IOException e) {
          Gdx.app.log("PingPongSocketExample", "an error occured", e);
        }
      }
    }).start();

    // create the client send a message, then wait for the
    // server to reply
    // 		SocketHints hints = new SocketHints();
    // 		Socket client = Gdx.net.newClientSocket(Protocol.TCP, "localhost", 9999, hints);
    // 		try {
    // 			client.getOutputStream().write("PING\n".getBytes());
    // 			String response = new BufferedReader(new InputStreamReader(client.getInputStream())).readLine();
    // 			Gdx.app.log("PingPongSocketExample", "got server message: " + response);
    // 		} catch (IOException e) {
    // 			Gdx.app.log("PingPongSocketExample", "an error occured", e);
    // 		}
  }
}

The server waits for a client to connect for a few seconds and throws an exception:

Exception in thread "Thread-7" com.badlogic.gdx.utils.GdxRuntimeException: Error accepting socket.
  at com.badlogic.gdx.backends.lwjgl.LwjglServerSocket.accept(LwjglServerSocket.java:83)
  at HelloWorldWebsocket.WebsocketClient$1.run(WebsocketClient.java:44)
  at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.SocketTimeoutException: Accept timed out
  at java.net.PlainSocketImpl.socketAccept(Native Method)
  at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409)
  at java.net.ServerSocket.implAccept(ServerSocket.java:545)
  at java.net.ServerSocket.accept(ServerSocket.java:513)
  at com.badlogic.gdx.backends.lwjgl.LwjglServerSocket.accept(LwjglServerSocket.java:80)

How to change the example so that the server waits indefinitely for the client to connect?