This repository contains a barebones WebSocket server and client implementation written in 100% Java. The underlying classes are implemented java.nio, which allows for a non-blocking event-driven model (similar to the WebSocket API for web browsers).
The chat client is a simple Swing GUI application that allows you to send messages to all other connected clients, and receive messages from others in a text box.
In the example folder is also a simple HTML file chat client chat.html, which can be opened by any browser. If the browser natively supports the WebSocket API, then it's implementation will be used, otherwise it will fall back to a Flash-based WebSocket Implementation.
Writing your own WebSocket Server
The org.java_websocket.server.WebSocketServer abstract class implements the server-side of the WebSocket Protocol. A WebSocket server by itself doesn't do anything except establish socket connections though HTTP. After that it's up to your subclass to add purpose.
Writing your own WebSocket Client
The org.java_websocket.client.WebSocketClient abstract class can connect to valid WebSocket servers. The constructor expects a valid ws:// URI to connect to. Important events onOpen, onClose, onMessage and onIOErrorget fired throughout the life of the WebSocketClient, and must be implemented in your subclass.
This library supports wss. To see how to use wss please take a look at the examples.
If you do not have a valid certificate in place then you will have to create a self signed one. Browsers will simply refuse the connection in case of a bad certificate and will not ask the user to accept it. So the first step will be to make a browser to accept your self signed certificate. ( https://bugzilla.mozilla.org/show_bug.cgi?id=594502 ). If the websocket server url is wss://localhost:8000 visit the url https://localhost:8000 with your browser. The browser will recognize the handshake and allow you to accept the certificate. This technique is also demonstrated in this video.
The vm option -Djavax.net.debug=all can help to find out if there is a problem with the certificate.
It is currently not possible to accept ws and wss connections at the same time via the same websocket server instance.
For some reason firefox does not allow multible connections to the same wss server if the server uses a different port than the default port(443).
If you want to use wss on the android platfrom you should take a look at this.
I ( @Davidiusdadi ) would be glad if you would give some feedback whether wss is working fine for you or not.
Minimum Required JDK
Java-WebSocket is known to work with:
Java 1.5 (aka SE 6)
Android 1.6 (API 4)
Other JRE implementations may work as well, but haven't been tested.
Testing in Android Emulator
Please note Android Emulator has issues using IPv6 addresses. Executing any socket related code (like this library) inside it will address an error