java - 接口(interface)隐式声明 Object 类的公共(public)方法？

Question

这个问题在这里已经有了答案:





How methods of Object class be visible through interface?

(1 个回答)


2个月前关闭。




根据 The Java Language Specification, Java SE 16 Edition (JLS) §9.2 Interface Members :

If an interface has no direct superinterface types, then the interface implicitly declares a public abstract member method m with signature s, return type r, and throws clause t corresponding to each public instance method m with signature s, return type r, and throws clause t declared in Object (§4.3.2), unless an abstract method with the same signature, same return type, and a compatible throws clause is explicitly declared by the interface.

为什么任何顶级接口(interface)“隐式”声明 的公共(public)方法对象 类(class)？这个设计的目的是什么？

Answer 1

What is the purpose of this design?

因为你希望能够拨打所有 Object 任何类型的每个对象上的方法( toString 、 equals 、 hashCode 等)。

interface Foo {
  
}

Foo foo = ...;

foo.equals(otherFoo);

我是否真的声明了 equals 并不重要接口(interface)中的方法。