Java多线程--两个线程同时对一个人的年龄进行增加和修改

 public class Thread_A extends Thread {
     Human human;

     public Thread_A(String name, Human human) {
         super(name);
         this.human = human;
     }

     @Override
     public void run() {
         for (int i = 0; i < 100; i++) {
             human.setAge(human.getAge()+1);
             System.out.println(getName()+"线程实现Human的年龄+1，当前年龄："+human.getAge());
         }

     }
 }

 public class Thread_B extends Thread {
     Human human;

     public Thread_B(String name,Human human) {
         super(name);
         this.human = human;
     }

     @Override
     public void run() {
         for (int i = 0; i < 100; i++) {
             human.setAge(human.getAge()-1);
             System.out.println(getName()+"线程实现Human的年龄-1，当前年龄："+human.getAge());
         }
     }
 }

 public class TestThread {
     public static void main(String[] args) {
         Human human = new Human("张三", 10);
         Thread t1 = new Thread(new Thread_A("A",human));
         Thread t2 = new Thread(new Thread_B("B",human));
         t1.start();
         t2.start();
     }
 }

 @SuppressWarnings("all")
 public class Human {
     private String name;
     private int age;

     public Human() {
     }

     public Human(String name, int age) {
         this.name = name;
         this.age = age;
     }

     public int getAge() {
         return age;
     }

     public synchronized void setAge(int age) {
         if (age>0){
             this.age = age;
         }else {
             this.age = 0;
         }
     }

     @Override
     public String toString() {
         return "Human{" +
                 "name='" + name + '\'' +
                 ", age=" + age +
                 '}';
     }
 }