Java多个类继承

package 继承;

class Root
{
    static{
        System.out.println("Root的静态初始化块");
    }
    
    {
        System.out.println("Root的普通初始化块");
    }
    
    public Root()
    {
        System.out.println("Root的无参数的构造器");
    }
}


class Mid extends Root
{
    static{
        System.out.println("Mid的静态初始化块");
    }
    
    {
        System.out.println("Mid的普通初始化块");
    }
    
    public Mid()
    {
        System.out.println("Mid的无参数的构造器");
    }
    
    public Mid(String msg)
    {
        //通过this调用同一类中重载的构造器
        this();
        System.out.println("Mid的带参数构造器，其参数值：" + msg);
    }
}

class Leaf extends Mid
{
    static{
        System.out.println("Leaf的静态初始化块");
    }
    {
        System.out.println("Leaf的普通初始化块");
    }    
    public Leaf()
    {
        //通过super调用父类中有一个字符串参数的构造器
        super("Java初始化顺序演示");
        System.out.println("执行Leaf的构造器");
    }

}

public class TestStaticInitializeBlock
    {
        public static void main(String[] args) 
        {
            new Leaf();
        }
}

package 类与继承;

public class Test { 
    public static void main(String[] args)  { 
        new Circle(); 
    } 
} 
  
class Draw { 
      
    public Draw(String type) { 
        System.out.println(type+" draw constructor"); 
    } 
} 
  
class Shape { 
    private Draw draw = new Draw("shape"); 
      
    public Shape(){ 
        System.out.println("shape constructor"); 
    } 
} 
  
class Circle extends Shape { 
    private Draw draw = new Draw("circle"); 
    public Circle() { 
        System.out.println("circle constructor"); 
    } 
}