Question

Please help me explaning this. I can’t seem to figure out why this produce a null pointer exception

/* Try to find customer in customer list, if not in list add to list with a 
new plan; otherwise add additional plan to customer*/


for(int a = 0; a < dataset.length; a++){

       if(customer_name_list.contains(dataset[a][CLIENT_NAME])){
            int temp_index = 0;

//NULLPOINTEREXCEPTION OCCURRED ON THE FOLLOWING LINE 
            while(!customer.get(temp_index).name.equals(dataset[a][CLIENT_NAME])){
                temp_index++;
            }
            customer.get(temp_index).add_plan(dataset[a][PLAN], dataset[a][DETAIL]);
       }

       else{
                Customer temp_customer = new Customer(dataset[a][CLIENT_NAME], dataset[a][PLAN], dataset[a][DETAIL]);

       customer.add(temp_customer);
       customer_name_list.add(dataset[a][CLIENT_NAME]);
       }
   }

Thank you for your help

Answer 1

Taking this as the line the exception occurs on:

while(!customer.get(temp_index).name.equals(dataset[a][CLIENT_NAME])){

There’s a number of things that could be calling the issue. First off, customer could be null. Second, the results of customer.get(temp_index) could be null. Finally, customer.get(temp_index).name could also be null.

Since we’re not working with the full code set here, I suggest you step through and print out the values to each of the above things to work out what one’s null (or use a debugger.) That way you’ll be able to see exactly what’s causing the exception. My guess is that a customer’s name may well be set to null which would cause the issue, but it could just as easily be any of the other things I mentioned.