JavaCore-理解多態-運行時行爲

package com.atguigu.java5;


import java.util.Random;

//面試題：多態是編譯時行爲還是運行時行爲？
//證明如下：
class Animal  {
 
	protected void eat() {
		System.out.println("animal eat food");
	}
}

class Cat  extends Animal  {
 
	protected void eat() {
		System.out.println("cat eat fish");
	}
}

class Dog  extends Animal  {
 
	public void eat() {
		System.out.println("Dog eat bone");

	}

}

class Sheep  extends Animal  {
 

	public void eat() {
		System.out.println("Sheep eat grass");

	}

 
}

public class InterviewTest {

	public static Animal  getInstance(int key) {
		switch (key) {
		case 0:
			return new Cat ();
		case 1:
			return new Dog ();
		default:
			return new Sheep ();
		}

	}

	public static void main(String[] args) {
		int key = new Random().nextInt(3);

		System.out.println(key);

		Animal  animal = getInstance(key);
		
		animal.eat();
		 
	}

}