java - Java 8 中接口(interface)方法的隐式说明符/修饰符是什么？

Question

我知道接口(interface)方法是隐式的public。 Java Docs Tutorial说

All abstract, default, and static methods in an interface are implicitly public, so you can omit the public modifier.

在 abstract、static 和 default 之外，哪些修饰符在 Java 8 中被隐式声明。

我认为 abstract 不再隐式声明，因为 Java 8 在接口(interface)中引入了 default 方法，但我仍然收到 Intellij IDEA 中的警告 .

Modifier 'abstract' is redundant for interface methods.

public interface TestInterface {
    abstract int print();  // abstract redundant ?.
    int print2(); //legal.but public or public abstract ?.
}

Answer 1

language spec - 特别是第 9.4 节，声明 abstract 和 public 是隐式的。

Every method declaration in the body of an interface is implicitly public (§6.6). It is permitted, but discouraged as a matter of style, to redundantly specify the public modifier for a method declaration in an interface.

An interface method lacking a default modifier or a static modifier is implicitly abstract, so its body is represented by a semicolon, not a block. It is permitted, but discouraged as a matter of style, to redundantly specify the abstract modifier for such a method declaration.

这就是 IntelliJ 警告您的原因；通过 JLS，您正在做一些完全多余的事情。

作为奖励，fields in interfaces是隐式的public static final:

Every field declaration in the body of an interface is implicitly public, static, and final. It is permitted to redundantly specify any or all of these modifiers for such fields.