java多态中哪些成员具备多态特性

class Father{
    public static int x=10;
    public int y=11;
    public Father(){
        System.out.println("Father");
    }
    public static void info(){
        System.out.println("Father‘s static info method!");
    }
    public void test(){
        System.out.println("Father‘s  test method!");
    }
}

class Child extends Father{
    public static int x=20;
    public int y=21;
    public Child(){
        System.out.println("Childer");
    }
    public static void info(){
        System.out.println("Childer‘s static info method!");
    }
    public void test(){
        System.out.println("Childer‘s  test method!");
    }
}
public class HaHa {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Father father = new Father();       //父类的声明
        System.out.println(father.x);        //父类中的静态成员变量
        System.out.println(father.y);        //父类中的非静态变量
        father.info();                        //父类中的静态方法
        father.test();                       //父类中的非静态方法
        
        Child child = new Child();        //子类的声明
        System.out.println(child.x);
        System.out.println(child.y);
        child.info();
        child.test();
        
        Father fc = new Child();        //将子类的对象赋值给父类的对象
        System.out.println(fc.x);        
        System.out.println(fc.y);
        fc.info();
        fc.test();
    }

}