supersubconvert.java

软通公司培训的课件和习题里面有答案。。。

package com.iss.five;

class Employee{
	
	String name ;
	public void getEmployee(Employee e){
		System.out.println("Employee");
	}
}


public class SuperSubConvert extends Employee {

	public static void main(String[] args) {
		
		Employee e  = new Employee();
		SuperSubConvert s = new SuperSubConvert();
		Employee emp = new SuperSubConvert();       // 正确 子类对象可以视作父类对象
		e.getEmployee(e);
		s.getEmployee(s);           // 可以用子类的实参替代父类形参
		s = (SuperSubConvert)e ;    // 可以将父类强制转换为子类	
	}
}