Question

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why we need interface in java?

I refered the following link

prevoius post

can anyone explain any reason why we are using interface in java?

Other than

• multiple inheritance is possible with interfaces.
• polymorphism

Answer 1

Other than what you have mentioned, interfaces are a good way of exposing a set of functions (API) without divulging any information on their implementation.

By definition, when a class implements an Interface, it is agreeing to implementing a series of methods. This will allow any caller to use these methods without:

• The caller having to worry about how is the function implemented;
• Whoever wrote the function to worry about exposing internal logic.