[英]What is the difference between directly instantiating an ArrayList, rather than first declaring a List and then instantiating an ArrayList from it? [duplicate]
每当创建 ArrayList 的实例时，我经常想知道，为什么一些代码示例经常使用：
private List<things> listOfThings = new ArrayList<>();
相对于：
private ArrayList<things> listOfThings = new ArrayList<>();
每种方法的主要区别是什么？ 这些方法的优点和缺点是什么？
声明List之间有什么区别 <Integer> vs ArrayList <Integer> ？
[英]What is the difference between declaring List<Integer> vs ArrayList<Integer>?
在Activity中声明最终变量并在onCreate方法上实例化它之间有什么区别？
[英]What is the difference between declaring a final variable in an Activity and instantiating it on the onCreate method?
在字段中实例化和在构造函数中实例化之间有什么区别？
[英]What's the difference between instantiating in the field and instantiating in the constructor?
ArrayList <？>，ArrayList，ArrayList <Object>有什么区别？
[英]What is the difference between ArrayList<?>, ArrayList, ArrayList<Object>?
声明ArrayList对象和List对象在时间和空间复杂度上有什么区别？
[英]What is the difference in time & space complexity between declaring an ArrayList object and a List object?
“ArrayList <A>”和“ArrayList”</a>之间的实际区别是什么？ <? extends A> <A>“？</a>
[英]What is the practical difference between “ArrayList<A>” and “ArrayList<? extends A>”?
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