# Why do I get this null pointer exception? [closed]

When I execute this code it gives me the Exception Glthread 8 Java.lang.null.pointer

MouseJointDef md = new MouseJointDef();
md.bodyA = _body;
md.bodyB = _body;
md.target.set(locationWorld);
md.collideConnected = true;
md.maxForce = 1000.0f * _body.getMass();

_mouseJoint =  (MouseJoint) _world.createJoint(md);
_body.setAwake(true);


Thanks.

• Which line exactly? – Maik Semder Aug 13 '11 at 10:47
• Body A and B are the same for the joint? You sure that makes sense? – Maik Semder Aug 13 '11 at 10:48
• Voted to close as too localized. Make use of the debugger? – bummzack Aug 13 '11 at 11:10
• Have you stepped through the code in a debugger to see which variable is null? – ChrisF Aug 13 '11 at 13:31
• GDSE is not a debugger – Ray Dey Aug 13 '11 at 15:20

This is a case of "give a man a fish/teach a man to fish". You should learn to use the debugger to figure this problem out yourself.

Here is a good place to start:

http://www.infinitezest.com/articles/debugging-an-android-application.aspx

and you can find more here:

FWIW as your code stands, the most likely perpetrator are md.target, _body and _world.