Java继承和多态

class Father{
	public int s=20;
	public void prints(){
		System.out.println("Hello Father " + s);
	}
}
public class HelloWorld extends Father {
	int s=30, t=40;
	public void prints(){
		System.out.println("Hello World " + s);
	}

	public static void main(String[] args) {
		Father tmp = new HelloWorld();
		tmp.prints();
		System.out.println(tmp.s);
		/*Scanner reader = new Scanner(System.in);
		while(reader.hasNextInt()){
			int tmps = reader.nextInt();
			System.out.printf("%03d\n",tmps);
		}*/
	}
}

输出：

Hello World 30
20

注意方法是覆盖，类的变量是隐藏，不能实现覆盖。而多态只对覆盖关系才能体现出来。