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java.lang.NullPointerException - canot find why

Peter Miklosko
Ranch Hand

Joined: May 26, 2009
Posts: 76
I'm little experimenting with FileConnection.
So far I put together this code








but when I run it I will get following errors
Anuj Prashar
Ranch Hand

Joined: Apr 15, 2008
Posts: 99

I think exception is because in MobileFileBrowser midlet changescreen method that you are calling from startApp, you are creating an instance of
of class browser.gui.FileConnDetection. Now in FileConnDetection constructor you are using mgr instance variable that has not been initialised yet.
So it is throwing null pointer exception.
Peter Miklosko
Ranch Hand

Joined: May 26, 2009
Posts: 76
Yes, I came to same conclusion. I was about to make some correction to code when I went little "off project" starting doing something else. Hopefully in week or two I will get back to it and post correction so other can have look at it.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: java.lang.NullPointerException - canot find why