易百教程

70、以下 Java 程序的输出是什么?

class Person   
{  
    public Person()   
    {  
        System.out.println("Person class constructor called");  
    }  
}  
public class Employee extends Person   
{  
    public Employee()   
    {  
        System.out.println("Employee class constructor called");  
    }  
    public static void main (String args[])  
    {  
        Employee e = new Employee();  
    }  
}

运行结果:

Person class constructor called
Employee class constructor called

解释:如果派生类构造函数中没有显式包含 super()this(),则编译器会隐式调用 super()。 因此,在这种情况下,首先调用 Person 类构造函数,然后调用 Employee 类构造函数。