saravanan ragunathan wrote:. . .because abstract class has atleast one or more abstract methods(method without definition ) . . .
As Rob has already said, that is not quote correct. The reason is that "abstract" means untouchable and not solid, so it is used in Java™ to mean "don't create any objects of this class".
You
can actually create instances of an abstract class as an anonymous class, but that is a different story.