Minor Description
In HBaseClient#call, we have
connection.sendParam(call); // send the parameter boolean interrupted = false; //noinspection SynchronizationOnLocalVariableOrMethodParameter synchronized (call) { while (!call.done) { try { call.wait(); // wait for the result
sendParam could do nothing if the connection is closed right after the call is added into the queue. Since the connection is closed, we won't get any response, therefore, we won't get any notify call. So we will keep waiting here for something won't happen.