#vulnerable code 
                                @Override
    public void receiveResponse(CoapResponse coapResponse) {
        if (receiveEnabled)  {
            receivedResponses.put(System.currentTimeMillis(), coapResponse);
        }
    } 
                            #location 3 
                            #vulnerability type THREAD_SAFETY_VIOLATION
#fixed code
                                @Override
    public void receiveResponse(CoapResponse coapResponse) {
        receivedResponses.put(System.currentTimeMillis(), coapResponse);
    }