Useful message about NullPointerException

pike pike630 at
Tue Jan 27 11:47:07 UTC 2015

Bernd Eckenfels-4 wrote
> Am Wed, 21 Jan 2015 05:45:08 -0700 (MST)
> schrieb pike <

> pike630@

> >:
>> We frequently see NullPointerException in our logs. It's really a big
>> headache when we see a NullPointerException and it is encapsulated in
>> another exception as we don't know which object is null and it is
>> throwing an Exception. Is there any way we can get to know the object
>> type or the object variable name where the object is null and it is
>> throwing a NullPointerException? i.e, instead of just saying there is
>> a NullPointerException, can we add some friendly message? 
> Note that if you keep the stack information in an exception it points
> (most of the time) exactly to the location where the null access
> happens.
> I can imagine it is rather hard for the VM to add more informations.
> Your best bet is to avoid the NPEs and log the exceptions properly.
> Gruss
> Bernd

This is acually not helpful in some situations. For example, as what kedar
has mentioned, if there is a call "a.getB().getC()" and a NPE  is thrown.
There might be two situations:
1. a is null;
2. a.getB() is null

So it would be better if there can be one friendly message which indicates
what is null.

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