The Http2TestServerConnection class in the httpclient test library currently uses SSLSocket.getSession() to wait for the handshake to complete. The disadvantage of this is that it doesn't propagate back to the test any exception that can occur during the handshake. The test will still fail because the returned SSLSession is checked to see if the handshake succeeded or not, but it will be hard to diagnoze the underlying handshake failure cause since the exception isn't propagated back.