Can we create an instance of an interface in Java? [duplicate]

This question already has answers here: Can we create an object of an interface? (6 answers) Closed 7 years ago.

Is it possible to create an instance of an inter开发者_高级运维face in Java?

Somewhere I have read that using inner anonymous class we can do it as shown below:

interface Test {
    public void wish();
}

class Main {
    public static void main(String[] args) {
        Test t = new Test() {
            public void wish() {
                System.out.println("output: hello how r u");
            }
        };
        t.wish();
    }
}

cmd> javac Main.java
cmd> java Main
output: hello how r u

Is it correct here?

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You can never instantiate an interface in java. You can, however, refer to an object that implements an interface by the type of the interface. For example,

public interface A
{
}
public class B implements A
{
}

public static void main(String[] args)
{
    A test = new B();
    //A test = new A(); // wont compile
}

What you did above was create an Anonymous class that implements the interface. You are creating an Anonymous object, not an object of type interface Test.

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Yes, your example is correct. Anonymous classes can implement interfaces, and that's the only time I can think of that you'll see a class implementing an interface without the "implements" keyword. Check out another code sample right here:

interface ProgrammerInterview {
    public void read();
}

class Website {
    ProgrammerInterview p = new ProgrammerInterview() {
        public void read() {
            System.out.println("interface ProgrammerInterview class implementer");
        }
    };
}

This works fine. Was taken from this page:

http://www.programmerinterview.com/index.php/java-questions/anonymous-class-interface/

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Normaly, you can create a reference for an interface. But you cant create an instance for interface.

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Short answer...yes. You can use an anonymous class when you initialize a variable. Take a look at this question: Anonymous vs named inner classes? - best practices?

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No in my opinion , you can create a reference variable of an interface but you can not create an instance of an interface just like an abstract class.

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Yes it is correct. you can do it with an inner class.

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Yes we can, "Anonymous classes enable you to make your code more concise. They enable you to declare and instantiate a class at the same time. They are like local classes except that they do not have a name"->>Java Doc