Java EE 8 Cookbook

How to do it...

1. The first thing we need is our server endpoint:

@Singleton@ServerEndpoint(value = "/asyncServer")public class AsyncServer {        private final List<Session> peers = Collections.synchronizedList(new ArrayList<>());        @OnOpen    public void onOpen(Session peer){        peers.add(peer);    }        @OnClose    public void onClose(Session peer){        peers.remove(peer);    }        @OnError    public void onError(Throwable t){        System.err.println(t.getMessage());    }        @OnMessage    public void onMessage(String message, Session peer){        peers.stream().filter((p) ->         (p.isOpen())).forEachOrdered((p) -> {            p.getAsyncRemote().sendText(message +             " - Total peers: " + peers.size());        });    }}

2. Then, we need a client to communicate with the server:

@ClientEndpointpublic class AsyncClient ...