#fixed code
                             public V put(K key, V value) {
		return (V)doOp(ClusterOperation.CONCURRENT_MAP_PUT, Serializer.toByte(key), Serializer.toByte(value));
	}
#vulnerable code 
                             public V put(K key, V value) {
	    Packet request = createRequestPacket();
	    
	    request.setTxnId(0);
	    request.setOperation(ClusterOperation.CONCURRENT_MAP_PUT);
	    request.setKey(Serializer.toByte(key));
	    request.setValue(Serializer.toByte(value));
	    
	    
	    Packet response = callAndGetResult(request);
	    if(response.getValue()!=null){
	    	return (V)Serializer.toObject(response.getValue());
	    }
	    return null;
	} 
                            #location 11 
                            #vulnerability type NULL_DEREFERENCE