为啥我的if语句直接跳过了

public class Test {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String a;
        boolean flag = true;
        System.out.println("请确认选择 1（确定） or 2（取消）");
        a = scanner.next();
        if (a == "确定"){
            flag = false;
        }
        System.out.println(flag);
    }
}

if (a == "确定"){

改 为：a.equals("确定")

a也是确定

感谢