I don't know if I could make a new Topic or my problem is already be cleared...
anyway, i think I have problems in understanding Java and one of them is that i don't really feel the difference between Abstract Classes and Interfaces...
Abstract Class has a certain behavior and some methods, abstract of course...
On the other hand Interface inherit specific characteristics.
so what's the difference? because i think that i say the same thing twice...

Hai ,

Abstract class in Like Normal Class.But Has some methods which dont have implemntation.Some methods may have implemntation.Also the class is declared as abstract.If a class derived from the abstract class ,the deriving class must provide implemntation for all the abstract base class methods(ie methods without implementation)

But The Interfaces contain purely the prototypes of methods.And Dont Have any Implementation.The deriving class must implemnt all the methods defined in the Interface

i see...and thank you very much...
Also Interface's variables are always public static final ...
only these are the differences? what about inheritance?
the methods in Interfaces can be abstrant?

Hai,
FIrst U must understand that meaning of Abstract means 'Not Complete' .The Class can be said complete if it has all methods implemented.So Abstract class cannot be instantiated using 'new' operator.The reason for using abstract class is we can write some generalised class in which some methods dont have implemntation. Now the Responsiblity of implemting the mthods is the one who derives the class.

The Another Main Difference between abstract class and interface is.

1)we can derive abstract class only when it make sense.Our clas smust pass 'is a test' with the base class.
eg. If abstract class is employee ,then we can can write manager class which derives from employee class.Because manager is a employee.
2)Interface can be used to implemented in the completely unrelated classes.

your answers were more than helpful... i always have them in my mind!