java继承问题,求大神帮帮忙,急求

用JAVA定义一个point类,含有一个print方法,再定义一个print方法,再定义一个类point3d,继承自父类point类,并覆盖父类的同名方法print().在main()方法中调用父类和子类的print().

public class Test {

public static void main(String[] args) {
    Point point = new Point();
    point.print();

    Point point1 = new Point3D();
    point1.print();
}

}

protected class Point {
    public void print() {
        System.out.println("Point print");
    }
}

public class Point3D extends Point {
    public void print() {
        System.out.println("Point3d print");
    }
}

谢谢,但是运行出错,麻烦你再改改

看这里:
http://ideone.com/cLrQZe

在线编译和运行通过

 /* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

class point
{
    public void print() { System.out.println("base"); }
}
class point3d extends point
{
    @Override
    public void print() { System.out.println("derived"); }
}

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        // your code goes here
        point p1, p2;
        p1 = new point();
        p1.print();
        p2 = new point3d();
        p2.print();
    }
}

输出
base
derived

再不对就是你的环境的问题了,不关程序的事了。

point应该是一个抽象基类,由子类继承,并重写父类方法。就像你经常会出于某种目的,重写自己的类(继承自Object类)的toString()方法。