LinkedList数据结构，为什么我们需要从其他构造函数调用空的默认构造函数 [英] LinkedList data structure, why we need to call empty default constructor from a different constructor

问题描述

在 java.util.LinkedList 类中，定义了2个构造函数，默认构造函数和参数化构造函数接受一个集合。在查看实现时，我看到参数化的构造函数具有 this（），基本上是在调用默认构造函数。

In java.util.LinkedList class, there are 2 constructors defined, default and parameterized that accepts a collection. When I looked at the implementation, I see that the parameterized constructor has this(), basically is calling the default constructor.

但是默认构造函数为空。因此，我很好奇这是否是调用默认构造函数的最佳实践，即使默认构造函数为空或背后没有任何原因。如果不调用默认构造函数，会发生什么情况。

But the default constructor is empty. So I was just curious if this is a best practice to call default constructor even if its empty or is there any reasoning behind this. What happens if we don't call default constructor.

GrepCode LinkedList实现

推荐答案

这并不是公认的良好做法。也许默认的构造函数在以前的版本中做了什么。也许开发人员认为这是一个好主意，因此，如果在默认构造函数中完成了其他一些操作，那么在其他构造函数中也将进行其他操作。如果您查看ArrayList，您会发现做出了不同的选择。

It's not really a recognized good practice. Maybe the default constructor did something in previous versions. Maybe the developer thought it would be a good idea, so that if something additional is done in the default constructor, it will also be done in the other one. If you look at ArrayList, you'll see that a different choice was made.

如果我们不调用默认构造函数会发生什么。

What happens if we don't call default constructor.

不调用默认构造函数。超类no-arg构造函数被隐式调用。

The default constructor is just not called. The superclass no-arg constructor is called implicitely.

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