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Innerclasses

 
Greenhorn
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Which statement is true about a non-static inner class?
A. It must implement an interface.
B. It is accessible from any other class.
C. It can only be instantiated in the enclosing class.
D. It must be final if it is declared in a method scope.
E. It can access private instance variables in the
enclosing object.
My answers are B,D,E.
Actual answer is E. How is it possible??
 
Desperado
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(B) Not if the inner class is private.
(D) Wrong. That's for local variables that are used in a local class.
That leaves (E).
 
Greenhorn
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Why is answer C not valid. Please explain
 
Wanderer
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Art- If it's public, you can instantiate it from anywhere, provided you have an instance of the outer class. E.g.:

 
Ranch Hand
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Answer C is a little tricky, not because of the concept but the semantics used in the question. The non-static inner class requires an instance of the outer class before it can be instantiated itself. The inner class however can be instantiated from outside of the outer class if it is declared protected, public or if it uses the default accessibility.
There's a real cool tutorial on this site titled "Getting in touch with your inner class"

[This message has been edited by Joe Java (edited March 03, 2000).]
 
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