#fixed code
                                protected void processAndClear(int processIndex, StreamEvent streamEvent) {
        ComplexEventChunk<StateEvent> retEventChunk =  new ComplexEventChunk<StateEvent>(false);
        ComplexEventChunk<StreamEvent> currentStreamEventChunk = new ComplexEventChunk<StreamEvent>(streamEvent, streamEvent, false);

        ComplexEventChunk<StateEvent> eventChunk = ((StreamPreStateProcessor) nextProcessors[processIndex]).processAndReturn(currentStreamEventChunk);
        if(eventChunk.getFirst() != null){
            retEventChunk.add(eventChunk.getFirst());
        }
        eventChunk.clear();

        if(querySelector!= null) {
            while (retEventChunk.hasNext()) {
                StateEvent stateEvent = retEventChunk.next();
                retEventChunk.remove();
                querySelector.process(new ComplexEventChunk<StateEvent>(stateEvent,stateEvent, false));
            }
        }

    }
#vulnerable code 
                                protected void processAndClear(int processIndex, StreamEvent streamEvent) {
        ComplexEventChunk<StateEvent> retEventChunk =  new ComplexEventChunk<StateEvent>(false);
        ComplexEventChunk<StreamEvent> currentStreamEventChunk = new ComplexEventChunk<StreamEvent>(streamEvent, streamEvent, false);
        synchronized (lockKey) {
            ComplexEventChunk<StateEvent> eventChunk = ((StreamPreStateProcessor) nextProcessors[processIndex]).processAndReturn(currentStreamEventChunk);
            if(eventChunk.getFirst() != null){
                retEventChunk.add(eventChunk.getFirst());
            }
            eventChunk.clear();
        }

        if(querySelector!= null) {
            while (retEventChunk.hasNext()) {
                StateEvent stateEvent = retEventChunk.next();
                retEventChunk.remove();
                querySelector.process(new ComplexEventChunk<StateEvent>(stateEvent,stateEvent, false));
            }
        }

    } 
                            #location 16 
                            #vulnerability type THREAD_SAFETY_VIOLATION