小编moh*_*ark的帖子

public class Foo {

    public static void main(String[] args) {
        foo();
        bar();
    }

    public static void foo() {
        String s = "str4";
        String s1 = "str" + s.length();
        System.out.println("(s==s1)" + (s1 == s));
     }

    public static void bar() {
        String s = "str4";
        String s1 = "str" + "4";
        System.out.println("(s==s1)" + (s1 == s));
    }
}

OUTPUT

(s==s1)false

(s==s1)true

在String s1 ="str"+ s.length(); s1 = str4的值但在double equal(==)检查期间在下一个sysout语句中结果为false

*/