How to establish communication between WebService RestFul Jersey with desktop application?

I'm developing a chat system, in it I have a Java desktop application that needs to communicate with a WebService (server) which will distribute the messages to all connected clients. What is the best way to do this?

I have a WebService RestFul Jersey running, with only one method that returns the data passed as URL parameters on the client. Here are the WS codes:

@Path("/chat")

    @GET
@Path("connect/{username}/{msg}/{ip}/{port}")
@Produces("application/json")
public String getConnection(@PathParam("username") String userName, @PathParam("msg") String msg, @PathParam("ip") String ip, @PathParam("port") int port){
    String result = "";
    if (msg.equals(null) || msg.equals("exit") || msg.equals("sair")){
        System.out.println("Desconectando...");
        result = "Descontado.";
    }else{
        result = "Usuário: "+userName+"\n"+
                "Mensagem: "+msg+"\n"+
                "IP: "+ip+"\n"+"Porta: "+port;
    }

    return result;
}

The customer code is below:

public static void main(String[] args) {
try {

    Client client = Client.create();

    WebResource webResource = client
       .resource("http://localhost:8080/Restful/chat/connect/Usuario/mensagem/192.168.0.2/8080");

    ClientResponse response = webResource.accept("application/json")
               .get(ClientResponse.class);

    if (response.getStatus() != 200) {
       throw new RuntimeException("Failed : HTTP error code : "
        + response.getStatus());
    }

    String output = response.getEntity(String.class);

    System.out.println("Output from Server .... \n");
    System.out.println(output);

  } catch (Exception e) {

    e.printStackTrace();

  }

}

When I start WS and run a client I get the following return: The problem is this: how do I have multiple WS clients sending and receiving messages at the same time?