package com.study18;public class TestOutet {//1.在局部内部类中访问到的变量必须是被final修饰的public void method() {final int num = 10;class A{public void a() {// num = 20; System.out.println(num); } } }//2.如果类B在整个项目中只使用一次,那么就没有必要单独创建一个B类,使用内部类就可以了。public Comparable method2() {class B implements Comparable{ @Overridepublic int compareTo(Object o) {// TODO Auto-generated method stubreturn 100; } }return new B(); } public Comparable method3() {//3.匿名内部类return new Comparable() { @Overridepublic int compareTo(Object o) {// TODO Auto-generated method stubreturn 200; } }; } public void test() { Comparable comparable = new Comparable() { @Overridepublic int compareTo(Object o) {// TODO Auto-generated method stubreturn 200; } }; comparable.compareTo(comparable.compareTo("abc")); } }