`hashCode`的默认实现是什么？[重复]-Whatisthedefaultimplementationof`hashCode`?[duplicate]

41  

Then this class inherits hashCode from one of its ancestors. If non of them overrides it, then Object.hashCode is used.

然后这个类从其祖先之一继承hashCode。如果不覆盖它，则使用Object.hashCode。

From the docs:

来自文档：

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

尽可能合理，Object类定义的hashCode方法确实为不同的对象返回不同的整数。 （这通常通过将对象的内部地址转换为整数来实现，但JavaTM编程语言不需要此实现技术。）

So default implementation is JVM-specific

因此，默认实现是特定于JVM的

15  

By default, methods that are not overriden are inherited from Object.

默认情况下，未覆盖的方法从Object继承。

If you look at that method's documentation, the return values are "[...] distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer [...])". The method in java.lang.Object is declared as native, which means the implementation is provided by the JVM and may vary depending on your runtime environment.

如果查看该方法的文档，返回值是“[...]不同对象的不同整数。（这通常通过将对象的内部地址转换为整数[...]）”来实现。 java.lang.Object中的方法声明为native，这意味着实现由JVM提供，并且可能因运行时环境而异。

A small example:

一个小例子：

Object o1 = new Object();
Object o2 = new Object();
System.out.println(o1.hashCode());
System.out.println(o2.hashCode());

prints (using my jdk6):

打印（使用我的jdk6）：

1660187542
516992923

A Hex representation of the hashCode() value is used in the default implementation of toString() by the way: Running System.out.println(o1) prints something like

hashCode（）值的十六进制表示形式在toString（）的默认实现中使用：运行System.out.println（o1）打印类似的东西

java.lang.Object@7a5e1077

4  

Object.hashcode() is a native method.

Object.hashcode（）是一种本机方法。

public native int hashCode();

public native int hashCode（）;

That means it's implemented in platform specific code and is exposed as a native method.

这意味着它是在特定于平台的代码中实现的，并作为本机方法公开。

code for the same will be a compiled code and not available withing JDK

相同的代码将是一个编译的代码，不能用于JDK

this existing question might provide more info.

这个现有问题可能会提供更多信息。