package com.aff.equals;

public class TestString {

    public static void main(String[] args) {

        String str1 = "AA";

        String str2 = "AA";

        String str3 = new String("AA");

        System.out.println(str1 == str2);// true

        System.out.println(str1.equals(str2));// true

        System.out.println(str1 == str3);// false

        System.out.println(str1.equals(str3));// true;

    }

}

输出结果：

true
true
false
true