group4.java

来自「Java Classic Examples是我买的两本书：《JAVA经典实例》和」· Java 代码 · 共 34 行

public class Group4
{
    public abstract class Student_abstract           //抽象内部类
    {
        int count;
        String name;
        public abstract void output();               //抽象方法
    }
    public class Student extends Student_abstract    //继承抽象内部类
    {
        public Student(String n1)
        {
            name = n1;
            count++;                                 //Student.count
        }
        public void output()                         //实现抽象方法
        {
            System.out.println(this.name +"  count="+this.count);
        }
    }
    public Group4()
    {
        Student s1 = new Student("A");
        s1.output();
        Student s2 = new Student("B");
        s2.output();
    }
    public static void main (String args[])
    {
        Group4 g4 = new Group4();
    }
}