在在线编译器 jdoodle.com 上运行 java 并遇到一些问题

Question

这是我正在为多级继承练习的代码，但是当我运行它时，在线编译器会给我以下错误：

public class MyClass {
       ^
/grandFather.java:26: error: non-static method talking() cannot be referenced from a static context
      son.talking();
         ^
/grandFather.java:27: error: non-static method walking() cannot be referenced from a static context
      son.walking();
         ^
/grandFather.java:28: error: non-static method running() cannot be referenced from a static context
      son.running();

  

这是我正在运行的代码。 这是java中多级继承的练习代码。我创建了3个类（祖父，父亲和儿子）：

public class grandFather{
        int age;
        double height;
        
        public void talking(){
            System.out.println("Grandfather can walk");
        }
    }
    
    class father extends grandFather{
        public void walking(){
            System.out.println("Father can walk too");
        }
    }
    
    class son extends father{
        public void running(){
            System.out.println("Son can talk, walk and also run");    
        }
        
    }
    
    public class MyClass {
        public static void main(String args[]) {
          son kamran = new son();
          son.talking();
          son.walking();
          son.running();
        }
    }

Answer 1

基本上我在做：“son.talking()”而不是“kamran.talking”。

public class grandFather{
    int age;
    double height;
    
    public void talking(){
        System.out.println("Grandfather can walk");
    }
     public static void main(String args[]) {
      son kamran = new son();
      kamran.talking();
      kamran.walking();
      kamran.running();
    }
}

class father extends grandFather{
    public void walking(){
        System.out.println("Father can walk too");
    }
}

class son extends father{
    public void running(){
        System.out.println("Son can talk, walk and also run");    
    }
    
}