继承性

//子类对象实例化的全过程
public class TestDog {
    public static void main(String[] args) {
        Dog d = new Dog();
        d.setAge(10);
        d.setName("小明");
        d.setHostName("花花");
        System.out.println("name:" + d.getName() + " age:" + d.getAge()
                + " hostName:" + d.getHostName());		
        System.out.println(d.toString());
    }
}
// 生物
class Creator {
    private int age;
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Creator() {
        super();
        System.out.println("this is Creator's constructor");
    }
}
// 动物类
class Animal extends Creator {
    private String name;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Animal() {
        super();
        System.out.println("this is Animal's constructor");
    }
}
// 狗
class Dog extends Animal {
    private String hostName;
    public String getHostName() {
        return hostName;
    }
    public void setHostName(String hostName) {
        this.hostName = hostName;
    }
    public Dog() {
        super();
        System.out.println("this is Dog's constructor");
    }
}

this is Creator's constructor
this is Animal's constructor
this is Dog's constructor
name:小明 age:10 hostName:花花
Dog类的对象dd在堆空间内的信息