#fixed code
                                public void close() {
        closeInternal(true);
    }
#vulnerable code 
                                public void close() {
        synchronized (this) {
            state = ConnectionState.DISCONNECTED;
        }
        if (channel != null) {
            channel.close().awaitUninterruptibly();
        }
        if (readTimeoutTimer != null) {
            readTimeoutTimer.stop();
            readTimeoutTimer = null;
        }
    } 
                            #location 10 
                            #vulnerability type THREAD_SAFETY_VIOLATION