Do we need to declare interface methods as abstract

Question

Possible Duplicate:
Java abstract interface

public interface Foo {
   abstract public void bar();
}

I guess we don't need to declare abstract as well as public in the above interface. Will the compiler catch this is as a warning or is it allowed by the compiler.

The `abstract` modifier for Interfaces is [obsolete](http://stackoverflow.com/questions/641536/why-would-one-declare-a-java-interface-method-as-abstract). — Vineet Reynolds, Sep 02 '11 at 08:06

score 7 · Answer 1 · answered Sep 02 '11 at 08:06

7

In an interface the the modifiers public and abstract are implied for methods, similarly for fields public static and final are implied. For inner classes static is implied.

answered Sep 02 '11 at 08:06

Peter Lawrey

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score 6 · Answer 2 · answered Sep 02 '11 at 08:05

6

It is allowed. public and abstract are automatically added to every interface method.

answered Sep 02 '11 at 08:05

Petar Minchev

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score 5 · Accepted Answer · answered Sep 02 '11 at 08:05

5

You don't have to, every interface method is implicitly abstract. It will not be a mistake to write it though.

answered Sep 02 '11 at 08:05

amit

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score 3 · Answer 4 · answered Sep 02 '11 at 08:05

3

For interface methods, it is not necessary to declare public and abstract by default those are public and abstract

answered Sep 02 '11 at 08:05

developer

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score 3 · Answer 5 · answered Sep 02 '11 at 08:11

3

It is not necessary but it won't hurt to write it. These modifiers are implied.

I like to do it so everything is explicit and may help other programmers that will work with your code.

answered Sep 02 '11 at 08:11

rlc

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score 0 · Answer 6 · answered Sep 02 '11 at 08:13

You are allowed to declare abstract inside the interface. The complier can pass it.

public interface foointerface {

    abstract public void foo();

    public void bar();
}

But there is no point to declare in abstract since we would not implement or allow to implement methods inside interface.

Do we need to declare interface methods as abstract

6 Answers6