Question

I am having the following exception:

Exception in thread "main" java.lang.NullPointerException
    at Studentlist.Studentlist(Studentlist.java:79)
    at Studentlist.main(Studentlist.java:38)

on line 38:
I am passing to input to getstudentsprofile.

on line79:
I am doing :

int z= array1.length;

How to debug this issue.
I am reading lot of records and everything it is crashing at one place with this exception.
How to debug this? how can I see when the exception happened what are the values?

Infact I have :

catch (IOException ee)
        {
            ee.printStackTrace();
        }      

but no luck.

Answer 1

seems like array1 is null and NullPointerException is not a IOException so you need to catch

catch (NullPointerException npe) {
            npe.printStackTrace();
}

or even better don’t give your code to raise this condition for that statement, check for null

int z = SOME_DEFAULT_VALUE;
if(arr!=null){
 z = arr.length;
}