public class Test {
    public static void main(String[] args) {
        Son s = new Son();
        Parent p = (Parent)s;
        p.print();
        //p.foo();
    }
}
class Parent{
    void print(){
        System.out.println("parent print");
    }
}
class Son extends Parent{
    void print(){
        System.out.println("son print");
    }
    void foo(){
        System.out.println("son foo()");
    }
}