无聊的笔试题

非常无聊的笔试题：

public class Test {
    public static void main(String[] args) {
        String s1 = "a" +"b" + "c";
        String s2 = "abc";
        String s3 = new String("abc");

        System.out.println(s2 == s3);
        System.out.println(s2 == s1);
        System.out.println(s1.equals(s3));
        System.out.println(s2.equals(s3));

        Integer a = 100;
        Integer b = 100;
        Integer c = 100;
        System.out.println(a == b);
        System.out.println(a.equals(b));
    }
}

最终运行结果：

PS C:\Users\szy> & ‘C:\Program Files\Java\jdk-18.0.2\bin\java.exe’ ‘-agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=localhost:52582’ ‘-XX:+ShowCodeDetailsInExceptionMessages’ ‘-cp’ ‘C:\Users\szy\AppData\Local\Temp\vscodesws_c8069\jdt_ws\jdt.ls-java-project\bin’ ‘Test’
false
true
true
true
true
true`

解析：

== 比较的是内存地址
equal比较的是内容