继承—people

 public class People {

     private double height;//身高
     private double weight;//体重

     public double getHeight() {
         return height;
     }

     public void setHeight(double height) {
         this.height = height;
     }

     public double getWeight() {
         return weight;
     }

     public void setWeight(double weight) {
         this.weight = weight;
     }

     //方法打招呼
     public void speakHello(){
         System.out.println("hello ！");
     }

 //extends  继承
 public class ChinaPeople extends People {

     public void ChinaKongFu(){
         System.out.println("坐如钟，站如松。");
     }
     //重写   覆盖
     public void speakHello(){
         System.out.println("你好！");
     }
 }

 public class AmericanPeople extends People {

     public void americanBoxing(){
         System.out.println("直拳，左勾拳");
     }
 }

 public class Text_People {

     public static void main(String[] args) {
         People p1 = new People();
         p1.speakHello();

         ChinaPeople p2 = new ChinaPeople();
         p2.speakHello();
         p2.ChinaKongFu();

     }
 }

运行：