Java_002 method preliminary and code decompilation

public class Demo01 {
    
    
    //main方法
    public static void main(String[] args) {
    
    
        int sum = add(1,2);
        System.out.println(sum);
        test();
    }
    //加法
    public static int add(int a, int b){
    
    
        return a+b;
    }
    public static void test() {
    
    
        for (int i = 1; i <= 5; i++) {
    
    
            for (int j = 5; j >= i; j--) {
    
    
                System.out.print(" ");
            }
            for (int j = 1; j <= i; j++) {
    
    
                System.out.print("*");
            }
            for (int j = 1; j < i; j++) {
    
    
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

Output result:

3
     *
    ***
   *****
  *******
 *********

Decompile
Source code

public class Demo02 {
    
    
    public static int getSum (int x, int y){
    
    
        if (x <= 0 || y <= 0 ){
    
    
            return -1;
        }return x+y;
    }/*这样的程序对传入的参数值进行了检查控制；
       许多程序错误都是由非法参数引起的*/

    public static void main(String[] args) {
    
    
        int sum  = getSum(4, 5);
        System.out.println("Add 1 = "+sum);
        System.out.println("Add 2 = "+getSum(2, 4));
        getSum(6, 10);
    }
}

The result after decompilation

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package com.cuckoo.method;

public class Demo02 {
    
    
    public Demo02() {
    
    
    }

    public static int getSum(int x, int y) {
    
    
        return x > 0 && y > 0 ? x + y : -1;
    }

    public static void main(String[] args) {
    
    
        int sum = getSum(4, 5);
        System.out.println("Add 1 = " + sum);
        System.out.println("Add 2 = " + getSum(2, 4));
        getSum(6, 10);
    }
}