普通方法多态，属性，私有方法和静态方法不多态

public class B extends P {
    int a = 33;

    public B() {
        System.out.println("B" + a);
        a = 44;
        diplay();
    }

    @Override
    public void diplay() {
        System.out.println("I am in B, value is " + a);
    }
}

public class P {
        public int a = 11;

        public P() {
            System.out.println("P " + a);
            a = 22;
            diplay();
        }

        public void diplay() {
            System.out.println("I am in P, value is " + a);
        }
}

public class Test {
    public static void main(String[] args) {
        B b = new B();
        System.out.println(b.a);
    }

}