为什么将接口声明为抽象？ [英] Why declare an interface as abstract?

问题描述

将接口声明为抽象是什么意思？接口方法也是如此。有没有意义呢？

What's point of declaring an interface as abstract? Same thing for an interface method. Is there a point to it?

例如。

public abstract interface Presenter {
 public abstract void go(final HasWidgets container);
}

推荐答案

你在哪里遇到过您发布的代码块，任何旧的Java代码库？

这是 JLS 必须说：

Where did you come across the chunk of code you have posted, any old java code base ?
This is what the JLS has to say :

9.1.1.1抽象接口：

每个接口都是隐式抽象的。此修饰符已过时，不应在新程序中使用
。

9.1.1.1 abstract Interfaces:
Every interface is implicitly abstract. This modifier is obsolete and should not be used in new programs.

9.4抽象方法声明：

为了与旧版本的Java平台兼容，允许使用
作为样式，为接口中声明的方法冗余地指定抽象修饰符
。

9.4 Abstract Method Declarations:
For compatibility with older versions of the Java platform, it is permitted but discouraged, as a matter of style, to redundantly specify the abstract modifier for methods declared in interfaces.

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