#vulnerable code 
                                public void sendUpdate(STATUS status, Object message) {
        if (observer == null) {
            return;
        }
        synchronized (observer) {
            observer.update(this, new RipStatusMessage(status, message));
            observer.notifyAll();
        }
    } 
                            #location 5 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                public void sendUpdate(STATUS status, Object message) {
        if (observer == null) {
            return;
        }
        observer.update(this, new RipStatusMessage(status, message));
    }