This is really a beginners' question and my question is if an abstract class has all of its methods "abstract" in it(i.e. no concrete methods) then what will be the difference between this abstarct class and an interface.
If all your methods are abstract you are better off writing an interface, because you can implement several interfaces in the same class, but only extend one class. Remember you usually miss out "public" and "abstract" in method declarations in interfaces.
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