我是歌手Java实现

//AbstractSinger.java
package cn.campsg.java.experiment.entity;

public abstract class AbstractSinger {
    public void introduce() {
        System.out.println("Hello，我是歌手。");
    }

    public abstract void sing() ;
}

//PopSinger.java
package cn.campsg.java.experiment.entity;

public class PopSinger extends AbstractSinger{
    public void sing() {
        System.out.println("我是唱流行乐的。");
    }
}

//MainClass.java
package cn.campsg.java.experiment;

import cn.campsg.java.experiment.entity.AbstractSinger;
import cn.campsg.java.experiment.entity.PopSinger;

public class MainClass {
    public static void main(String[] args) {
        AbstractSinger s = new PopSinger();
        s.introduce();
        s.sing();
    }
}