classPerson{String name;int age;void eat(){System.out.println("吃饭");}void introduce(){System.out.println("我的名字是"+ name +"，我的年龄是"+ age);}}classStudent extends Person{int grade;void study(){System.out.println("学习");}}classTeacher extends Person{}classTest{publicstaticvoid main(String args []){Student student =newStudent(); student.name ="张三"; student.age =20; student.grade =3; student.eat(); student.introduce(); student.study();}}原文：http://www.cnblogs.com/arroneve/p/5815431.html