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Vinu Menon
Greenhorn

Joined: Jan 26, 2009
Posts: 20
Can any one tell me why i am getting null pointer exception in the below program




Thanks
Vinay.
Omar Al Kababji
Ranch Hand

Joined: Jan 13, 2009
Posts: 357
because in your case the variable (a) is for the first instance. however when you do


new Thread(new B()).start()

a new object of type B will be created and its instance vaiable (a) is still null. so you either have to initialize your (a) variable in the constructor of class B, or do that line of code like this


Omar Al Kababji - Electrical & Computer Engineer
[SCJP - 90% - Story] [SCWCD - 94% - Story] [SCBCD - 80% - Story] | My Blog
Stephen Davies
Ranch Hand

Joined: Jul 23, 2008
Posts: 352
Yup, check your references.


be a well encapsulated person, don't expose your privates, unless you public void getWife()!
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Threads