为什么 Java 中的每个对象都隐式扩展 java.lang.Object 类? [英] Why does every object in Java implicitly extend java.lang.Object class?

问题描述

我已经用 Java 编程有一段时间了，但是当我试图向朋友解释 java.lang.Object 类是什么时，我想不出比一个简单的单线:

I have been programming in Java for quite some time, but when I tried to explain what an java.lang.Object class is to a friend, I could not come up with more than a simple one-liner:

Java 中的所有对象都隐式扩展 java.lang.Object

All objects in Java extend java.lang.Object implicitly

我不太确定为什么要这样做.

I was not quite sure why it should do so.

所以，我查看了 GrepCode，希望能找到一些线索.现在我知道 java.lang.Object 是什么以及它的作用，我想知道是否有任何具体的原因来设计它.

So, I looked upon the source code on GrepCode, hoping that I can find some clues. Now I know what a java.lang.Object is and what it does, I want to know if there was any specific reason as to why it was designed this way.

我的问题仍然存在:为什么每个对象都应该扩展java.lang.Object?

My question still prevails: why should every object extend java.lang.Object?

推荐答案

我想说的原因是java中的所有对象都有一个通用的API来支持像

I would say that the reason is to have a common API for all objects in java to supports basic functionality like

• 同步 - wait、notify、notifyAll
• 垃圾收集 - finalize
• 集合支持 - hashCode、equals
• 对象克隆 - clone

• synchronization - wait, notify, notifyAll
• garbage collection - finalize
• collection support - hashCode, equals
• object cloning - clone

和每个对象

• 有一个它所属的类 - getClass
• 可以将自己表示为一个字符串，因为我们是人类并且可以读取字符串 - toString

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