Java 抽象类

我们需要知道，由于为抽象类创建对象是不安全的，所以我们会从编译器那里得到一条出错消息。这样，编译器会确保抽象类的纯粹性，我们不必担心会误用它。

编译器直接报错提醒。

看一下完整的例子：

abstract class Rodent{
	public abstract void play();
}

abstract class Mouse extends Rodent{
	public abstract void eat();
}

class Gerbil extends Mouse{

	@Override
	public void eat() {
		// TODO Auto-generated method stub
		System.out.println("eat!");
	}

	@Override
	public void play() {
		// TODO Auto-generated method stub
		System.out.println("play!");
	}
	
	public void sleep() {
		System.out.println("sleep!");
	}
	
}

public class Demo02 {
	public static void main(String[] args) {
		Rodent r1 = new Gerbil();
		r1.play();
		System.out.println("------------");
		Mouse m1 = new Gerbil();
		m1.eat();
		m1.play();
		System.out.println("------------");
		Gerbil g1 = new Gerbil();
		g1.eat();
		g1.play();
		g1.sleep();
		System.out.println("------------");
	}
}