Description
We encountered this NullPointerException today in production, and it caused the Websocket server to shut down. I had to restart our application server to get it operational again.
ERROR (WebSocketWorker-90) Websocket connection error from null
java.lang.NullPointerException
at org.java_websocket.WebSocketAdapter.getFlashPolicy(WebSocketAdapter.java:87)
at org.java_websocket.WebSocketImpl.decodeHandshake(WebSocketImpl.java:193)
at org.java_websocket.WebSocketImpl.decode(WebSocketImpl.java:161)
at org.java_websocket.server.WebSocketServer$WebSocketWorker.run(WebSocketServer.java:663)
2013-09-12 04:31:08,247 INFO (WebSocketWorker-90) Web socket server stopped
Here is the line that causes the NPE:
return "<cross-domain-policy><allow-access-from domain=\"*\" to-ports=\"" + conn.getLocalSocketAddress().getPort() + "\" /></cross-domain-policy>\0";conn.getLocalSocketAddress() is what's returning null here. Here's what it does:
return wsl.getLocalSocketAddress( this );And here's what that does:
return (InetSocketAddress) getSocket( conn ).getLocalSocketAddress();So the call to getLocalSocketAddress() here on java.net.Socket is returning null.
The Javadoc for this method says:
Returns the address of the endpoint this socket is bound to, or null if it is not bound yet.
I don't know why this method is getting invoked when the socket is not yet bound, but the bug is either that you're invoking this method before ensuring that the socket is bound (my guess), or that you need to handle a null return from getLocalSocketAddress().
Additionally, this exception (and all RuntimeExceptions) needs to be properly handled, and NOT cause the server to throw up its hands and shut down. I'll file a separate bug for this.