接口-大学里的学生（Student）需要交学费，而研究生（Graduate）作为学生比较特殊，除了需要交学费外，还可以获取一部分科研津贴，由学校（University）统一发放。此外，学校还需要发放教

package com.bzu.aa;


public abstract class Student {

String name;
int fee;

Student(String name){

}

abstract void setFee(int fee);
abstract int getFee();

}

package com.bzu.aa;
public interface Salary {

int getSalary();

}

package com.bzu.aa;


public  class Graduate extends Student implements Salary {

int salary;

Graduate(String name) {
super(name);
}

void setFee(int fee){
this.fee = fee;
}

int getFee(){
return 0;
}

public int getSalary(){

return this.salary=1500; 
}

boolean isLoan(){
if(this.salary<this.fee){
return true;
}
else
return false;

}


}

package com.bzu.aa;


public class Teacher implements Salary {
String name;
int salary;

Teacher(String name){

}

public int getSalary() {
return this.salary=3000;
}


}

package com.bzu.aa;


public class University {

void payOff(Salary s){
if(s instanceof Teacher){
s.getSalary();
}
else if(s instanceof Graduate){
s.getSalary();
}
}


}

package com.bzu.aa;


public class Test {


public static void main(String[] args) {
Graduate g = new Graduate("小亮");
g.setFee(1000);


University u = new University();
u.payOff(g);

System.out.println("是否需要贷款："+g.isLoan());


Teacher t = new Teacher("大王");
u.payOff(t);


}


}