Inner class doubt ?
Sim Kim
Ranch Hand
Posts: 268
posted 12 years ago
Suppose there is a question : Inner class has access to all variables of enclosing class ?
The answer should be True or False ?
Reason I am asking this is because if we consider inner class as both static and non-static inner class then this is False . But if we consider inner class as non-static inner class ( or method-local inner class defined inside non-static method) then this is true .
The answer should be True or False ?
Reason I am asking this is because if we consider inner class as both static and non-static inner class then this is False . But if we consider inner class as non-static inner class ( or method-local inner class defined inside non-static method) then this is true .
Mike Gershman
Ranch Hand
Posts: 1272
posted 12 years ago
I hope an exam question will be more specific.
Four kinds of variable:
static variable
instance variable
non-final local variable
final local variable
Four kinds of nested class:
static nested class
inner class
method-local inner class
anonymous inner class
This means 16 rules to learn.
Most of them are obvious, as with your example of static nested classes not having access to instance variables.
Some are subtle, like method-local classes not having access to non-final local variables.
But they can all be on the test.
Four kinds of variable:
static variable
instance variable
non-final local variable
final local variable
Four kinds of nested class:
static nested class
inner class
method-local inner class
anonymous inner class
This means 16 rules to learn.
Most of them are obvious, as with your example of static nested classes not having access to instance variables.
Some are subtle, like method-local classes not having access to non-final local variables.
But they can all be on the test.
Mike Gershman
SCJP 1.4, SCWCD in process
ankur rathi
Ranch Hand
Posts: 3830
Mike Gershman
Ranch Hand
Posts: 1272
posted 12 years ago
I was thinking more about this question.
Technically, static nested classes are not inner classes. On that basis, the answer is generally true.
The big exception is a static method-local class, which cannot directly access instance variables. However, that is equally true of static nested classes, static methods, and static initializers, so I would still answer your question "true".
Suppose there is a question : Inner class has access to all variables of enclosing class ?
I was thinking more about this question.
Technically, static nested classes are not inner classes. On that basis, the answer is generally true.
The big exception is a static method-local class, which cannot directly access instance variables. However, that is equally true of static nested classes, static methods, and static initializers, so I would still answer your question "true".
Mike Gershman
SCJP 1.4, SCWCD in process
Mike Gershman
Ranch Hand
Posts: 1272
posted 12 years ago
Rathi, what book are you using? I would rather point you to the correct section of your book than rewrite it here.
If you don't have a book, the author has generously made "Thinking in Java" available online for free here
http://www.mindview.net/Books/TIJ/
can you mention 16 rules ...
Rathi, what book are you using? I would rather point you to the correct section of your book than rewrite it here.
If you don't have a book, the author has generously made "Thinking in Java" available online for free here
http://www.mindview.net/Books/TIJ/
Mike Gershman
SCJP 1.4, SCWCD in process
ankur rathi
Ranch Hand
Posts: 3830
Barry Gaunt
Ranch Hand
Posts: 7729
posted 12 years ago
I've deleted a couple of sort of half off-topic posts here which were giving rise to a little friction heat...
[ January 11, 2005: Message edited by: Barry Gaunt ]
[ January 11, 2005: Message edited by: Barry Gaunt ]
Ask a Meaningful Question and HowToAskQuestionsOnJavaRanch
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