Would like examples of NullPointerExceptions for tool testing

[Alistair Hutton]

Desipte the ease with which I produce NullPointerExceptions
normally while programming I'm having a hard time coming up
with them to construct an example problem to demonstrate the
functionallity of the tool in my supplied docs. As a result
I'm wondering if any of you exceedingly helpful people would
be able to come up with a short example program/set of
classes that display a classic Null Pointer problem or better
yet, point me too a web page which has such an example on it.

 

[Roedy Green]

Desipte the ease with which I produce NullPointerExceptions
normally while programming I'm having a hard time coming up
with them to construct an example problem to demonstrate the
functionallity of the tool in my supplied docs. As a result
I'm wondering if any of you exceedingly helpful people would
be able to come up with a short example program/set of
classes that display a classic Null Pointer problem or better
yet, point me too a web page which has such an example on it.

One of the most common ones goes like this:

Button[] b = new Button[3];

b[0].setForeground( Color.red );

 

[Roedy Green]

One of the most common ones goes like this:

Button[] b = new Button[3];

b[0].setForeground( Color.red );

the notes at
http://mindprod.com/jgloss/errormessages.html#NULLPOINTEREXCEPTION
may help

 

[JavaJug]

Very easy :

String s = null;
s.length();

 

[Joona I Palaste]

Very easy :

String s = null;
s.length();

But:

Thread t = null;
t.currentThread();

Just goes to show that the "static methods via instance references"
trick is EEEVIL and should be forbidden.