java继承时候类的执行顺序有关问题

java继承时候类的执行顺序问题

子类在继承父类后，创建子类对象会首先调用父类的构造函数，先执行父类的构造函数，然后再执行子类的构造函数，如下所示：

class Father{
	public Father(){
		System.out.println("I am father");
	}
}
public class Child extends Father{
	public Child(){	
		System.out.println("I am child");
	}
	public static void main(String[] args) {
		Father f=new Father();
		Child c=new Child();
	}
}

当父类有带参数的构造函数时，子类默认是调用不带参数的构造函数，如下所示：

class Father{
	public Father(){
		System.out.println("I am father");
	}
	public Father(String name){
		System.out.println("I am father,My name is "+name);
	}
}
public class Child extends Father{
	public Child(){	
		System.out.println("I am child");
	}
	public static void main(String[] args) {
		Father f=new Father("Apache");
		Child c=new Child();
	}
}

若想子类调用父类带参数的构造函数，需要用super()函数申明，如下：

class Father{
	public Father(){
		System.out.println("I am father");
	}
	public Father(String name){
		System.out.println("I am father,My name is "+name);
	}
}
public class Child extends Father{
	public Child(){	
		super("Apache");
		System.out.println("I am child");
	}
	public static void main(String[] args) {
		Father f=new Father("Apache");
		Child c=new Child();
	}
}