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Thread: Question Regarding Interfaces

  1. #1
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    Default Question Regarding Interfaces

    I have a question.
    how do interface perform some task without having body in java. For example
    RequestDispatcher rd=request.getRequestDispatcher(“Login.html”);
    rd.include(request, response);

    My doubt is include method is not implemented. so how it is performing its tasks?????
    I am new to java


  2. #2
    Super Moderator helloworld922's Avatar
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    Default Re: Question Regarding Interfaces

    The actual object held by rd is not a direct RequestDispatcher instance, but rather another class which implements the RequestDispatcher interface. As such it must provide an implementation of all the methods RequestDispatcher requires. This is a guarantee enforced by the compiler.

    You can get the actual object type held:

    System.out.println(rd.getClass().getName());

    Note that the code won't always output something easily decipherable or make sense (particularly when dealing with nested/anonymous classes), but it will return what implementing class object is being held.

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