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inner class instantiation

 
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This is catalogue of inner class instantiations using new without a preceding object reference. (Not a question.)
Example 1.

The fourth one (at b2) surprised me.
 
Marlene Miller
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Example 2.
 
Marlene Miller
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Example 3.

This one is not intuitive. An inner class declared in a static context is okay. A static nested class declared in a static context is not okay.
 
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From example 3, it gives compiler error because only final or abstract can be declare in a method-local inner class. Is that the reason?
 
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It seems you can also use strictfp as a modifier as well in method-local inner classes... by itself or combined with either final or abstract....
Surprised this wasn't in the book, though it compiles fine with Sun's JDK.
 
Marlene Miller
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Good points. In example 3, only abstract, final and strictfp are valid modifiers. Thank you Andres and Toby.
(I wonder why static classes are not allowed. Some other day...)
 
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we cannot declare static class inside a method.
the same rule as local variables cannot be static and local variables also
cannot use the access modifiers.
this rule also appplied for local classes.
 
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Hi Marlene,
Those are good examples.
EXAMPLE 1:

Z() is an inner class so it requires an instance of the enclosing class and static methods does not have a reference to that instance
However, if the instance of the enclosing class is supplied, then the call would work:

EXAMPLE 2:
The problem with this code is that C.A() is the FQN of a member class which does not exists.
EXAMPLE 3
I always see static nested class as if it is inside a package with the outer class as its package. So that is why it can even be imported by other class. So static nested class are really like any top-level class.
I think it is not allowed to define static nested class inside a method because if it does, then it will loose some of the properties of a top-level class.
Just my $0.02.
 
Marlene Miller
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Thank you Krishna and Alton for your comments. Thank you to everyone for taking the time to read through the examples and say something.
Here is what I was trying to show with these examples: On the exam, we might see �new Z()� declared anywhere, and quick as a flash, we have to know whether it is valid or not. Will there be a compiler-error?
So I decided to list places where I might see new Z(). I also wanted to know if new C.Z() is valid where new Z() is valid.
What I wanted was to be able to say � if I know all this (the valid cases and the compiler errors), there is nothing more to know about instantiating named inner classes.
[ August 07, 2003: Message edited by: Marlene Miller ]
 
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