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Yes, you can't declare a variable twice.

But in the code you were asking about (#5) only one variable is declared (other than the loop variables): alpha. And it is declared just once.

The...

Yes, exactly.



Where would you expect the error? The point is you *did* initialise both alpha and each of the alpha[i] elements. Everything initialised == no NullPointerException.

Oddly,...

When you declare a variable of an array type ("Foo[] fooArr;") it will have the value null. (But in a method or constructor you simply can't use a variable you have declared there before it is...

Nice link, by the way.

Near the bottom - and garnering zero votes :( - we read:

"In Java every things is in the form of class.

If you want to use any object then you have two phases
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The NullPointerExpression will occur when you run the program. (Just a nitpick, but it pays to be precise...)

Could you post the stack trace: the long message that you get at the console when an...