fixed deadlock in server( TooTallNate#195 ) thanks @DeHecht for isolating the

problem

Author: Davidiusdadi

src/main/java/org/java_websocket/server/WebSocketServer.java

@@ -35,10 +35,12 @@
 importorg.java_websocket.WebSocketImpl;
 importorg.java_websocket.WrappedByteChannel;
 importorg.java_websocket.drafts.Draft;
+importorg.java_websocket.exceptions.InvalidDataException;
 importorg.java_websocket.framing.CloseFrame;
 importorg.java_websocket.framing.Framedata;
 importorg.java_websocket.handshake.ClientHandshake;
 importorg.java_websocket.handshake.Handshakedata;
+importorg.java_websocket.handshake.ServerHandshakeBuilder;
 
 /**
  * <tt>WebSocketServer</tt> is an abstract class that only takes care of the
@@ -200,15 +202,21 @@ public void start(){
  * @throws InterruptedException
  */
 publicvoidstop( inttimeout ) throwsIOException , InterruptedException{
-if( !isclosed.compareAndSet( false, true ) ){
+if( !isclosed.compareAndSet( false, true ) ){// this also makes sure that no further connections will be added to this.connections
 return;
  }
 
+List<WebSocket> socketsToClose = null;
+
+// copy the connections in a list (prevent callback deadlocks)
 synchronized ( connections ){
-for( WebSocketws : connections ){
-ws.close( CloseFrame.GOING_AWAY );
- }
+socketsToClose = newArrayList<WebSocket>( connections );
+ }
+
+for( WebSocketws : socketsToClose ){
+ws.close( CloseFrame.GOING_AWAY );
  }
+
 synchronized ( this ){
 if( selectorthread != null ){
 if( Thread.currentThread() != selectorthread ){
@@ -525,13 +533,25 @@ protected boolean removeConnection( WebSocket ws ){
  }
  }
 
+@Override
+publicServerHandshakeBuilderonWebsocketHandshakeReceivedAsServer( WebSocketconn, Draftdraft, ClientHandshakerequest ) throwsInvalidDataException{
+returnsuper.onWebsocketHandshakeReceivedAsServer( conn, draft, request );
+ }
+
 /** @see #removeConnection(WebSocket) */
 protectedbooleanaddConnection( WebSocketws ){
-synchronized ( connections ){
-returnthis.connections.add( ws );
+if( isclosed.get() ){
+synchronized ( connections ){
+booleansucc = this.connections.add( ws );
+assert ( succ );
+returnsucc;
+ }
+ } else{
+// This case will happen when a new connection gets ready while the server is already stopping.
+ws.close( CloseFrame.GOING_AWAY );
+returntrue;// for consistency sake we will make sure that both onOpen will be called
  }
  }
-
 /**
  * @param conn
  * may be null if the error does not belong to a single connection