Abstract classes are the partial implementation of Abstraction while Interfaces are the fully implementation of Abstraction.Means in Abstract classes we can put methods declaration as well as method body.
We can't create an object of Abstract classes(association) and reuse the class by inheritence(not by association).
By default in interfaces all declared variables are static final and All methods are public.
For Example: In JDK there are only few abstract classes and HttpServlet is one of them which is used in Servlet.So we can't create object of HttpServlet and it can be used only by inheritence.
