创建“新对象”与创建新对象之间的区别在于：和“类对象名称” [英] Difference between creating a "new object" and "Class objectname"

问题描述

例如，我有一个叫做Phone的类。

Say for example I have a class called Phone.

两者之间有什么区别？

Phone p;

和

Phone p = new Phone(200) //(200 is the price of the phone).

和

new Phone(200)

我已经在google上搜索甚至尝试过，但是可以

I've googled and even tried it on Eclipse but can't figure it out.

推荐答案

电话p; 仅声明一个引用处理程序 p 不会指向任何位置（它是未初始化的，除非您为其分配了某些内容，否则无法使用[感谢@Anthony]）。

Phone p; only declares a reference handler p which doesn't point anywhere (it is a not initialized and cannot be used until you assign something to it [thanks @Anthony]).

Phone p =新Phone（200）; 声明引用处理程序 p 指向新创建的 Phone 对象（由 Phone（200）初始化）。

Phone p = new Phone(200); declares a reference handler p which points to a newly created Phone object (initialized with Phone(200)).

新Phone（200）创建一个新的 Phone 对象，但是由于没有引用

new Phone(200) creates a new Phone object, but since no reference to it is stored anywhere, it becomes immediately eligible for garbage collection (unless its constructor stores a reference somewhere, that is).

_{（请注意，在Java中，所有类型为引用类型的变量实际上是引用处理程序。仅值类型的变量直接包含值。由于 Phone 是引用类型（它是类），因此 Phone p 始终是对 Phone 的引用。）}

_{(Note that in Java, all "variables" whose type is a reference-type are really reference handlers. Only variables of value-type contain values directly. Since Phone is a reference-type (it's a class), Phone p is always a "reference to a Phone".)}

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