Interview 3--java Collection Class summary

1. Collection classes

Arrays: You can store objects, or you can store basic data types, but only one type at a time, and the length must not be changed.

Collections: objects can be stored only, with varying lengths, and objects of different types may be stored.

Where the implementation of the border is the implementation class, the polyline border is an abstract class, the point line border is the interface

As you can see, the collection interface is the root interface of the collection class, and there is no direct implementation class for this interface in Java. There are three sub-interfaces List,set,queue, Note that map is not a collection sub-interface .

Methods in collection:

Interview 3--java Collection Class summary