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Please can any one tell me when I need use abstract class and interface I know what different but what useful of them at real time when I have project
 
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As Java does not support multiple inheritance, when you need to have a class (or abstract class) that contains various features, you have to use interfaces.

Nick
 
moneer mohammed
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ok but agian i need to impelement all the methods so no usefull
please give me example
 
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Hi,
Nicolas is right,When u have to use an abstract
class the methods in abstract class have to be
marked abstract,and when this class is subclassed,
subclass need to provide the relevant implementation for
each abstract method,while interfaces methods in Interfaces
are abstract by virtue of their declaration,and
should not be declared abstract.Also an Interface
is abstract by definition and therefore cannot
be instayiated.it should not be declared abstract.

 
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Originally posted by Nicholas Cheung:
As Java does not support multiple inheritance, when you need to have a class (or abstract class) that contains various features, you have to use interfaces.

Nick




Wow nick what a long list of degrees ?..a studious guy i shud say
 
It is sorta covered in the JavaRanch Style Guide.
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