JAVA Korean teacher class notes--1-22 lectures

1. The difference between abstract classes and interfaces:

Abstract classes are classes that cannot be instantiated, and are decorated by the abstract keyword.

An abstract method is a method that does not have a method body, that is, an empty method, a method that is specifically implemented by a quilt or extension class.

Interfaces are abstract classes that are more abstract, because non-abstract methods are allowed in abstract classes (even without an abstract method), and all methods in an interface must be abstract methods;

　　

2. Set FRAME (LinkedList, Arraylist, HashSet, HashMap,):

Advantage: No size limit.

JAVA Korean teacher class notes--1-22 lectures