OF-883 & OF-881: Avoid potential deadlock with close listeners.

The close listeners should not be called from within a synchronized block.

src/java/org/jivesoftware/openfire/nio/NIOConnection.java

@@ -208,8 +208,10 @@ public class NIOConnection implements Connection {
         return backupDeliverer;
     }
 
-    public synchronized void close()
+    public void close()
     {
+        boolean notifyClose = false;
+        synchronized ( this ) {
             try
             {
                 if ( state == State.CLOSED )
@@ -235,8 +237,7 @@ public class NIOConnection implements Connection {
                 // to invoke the CloseListeners again.
                 if ( state == State.CLOSING )
                 {
-                // TODO Check for regression of OF-881 (which placed the call below outside of the synchronized block).
-                notifyCloseListeners(); // clean up session, etc.
+                    notifyClose = true;
                 }
             }
             finally
@@ -250,6 +251,11 @@ public class NIOConnection implements Connection {
                 ioSession.close( true );
             }
         }
+        if (notifyClose)
+        {
+            notifyCloseListeners(); // clean up session, etc.
+        }
+    }
 
     public void systemShutdown() {
         deliverRawText("<stream:error><system-shutdown " +