接口、类

package zzy;
import static java.lang.System.*;
import java.util.*;
/**
 *
 * @author Zhu Zhengyan
 */
public class zzy14 {
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        Graduate yanjiusheng = new Graduate("zhangsan");
        out.println("Please enter the fee");
        yanjiusheng.setFee(in.nextInt());
        out.println("Please enter the pay");
        yanjiusheng.setPay(in.nextInt());
        yanjiusheng.jisuan();
    }
}


class Graduate implements StudentManageInterface,TeacherManageInterface
{
    private String name;
    private String sex;
    private int age;
    private int fee;
    private int pay;
    public Graduate(String name)
    {
        this.name = name;
        this.sex = null;
        this.age = 0;
        this.fee = 0;
        this.pay = 0;
    }
    public int setFee(int a)
    {
        this.fee = a;
        return fee;
    }
    public void getFee()
    {
        out.println(fee);
    }
    public int setPay(int a)
    {
        this.pay = a;
        return pay;
    }
    public void getPay()
    {
        out.println(pay);
    }
    public void jisuan()
    {
        if(fee - pay < 2000)
            out.println("provide a loan");
        else
            out.println("does not need");
    }
}
interface StudentManageInterface
{
    int setFee(int a);
    void getFee();
}
interface TeacherManageInterface
{
    int setPay(int a);
    void getPay();
}