public class Sports
{
    public static void main(String[] args)
    {
        Person per = new Person();
        Athlete ath = new Athlete();
        HighJumper hj = new HighJumper();
        ShotPutter sp = new ShotPutter();
        ExtremeAthlete ea = new ExtremeAthlete();
        XGamesSkater xgs = new XGamesSkater();


        Person[] people = { per, ath, hj, sp, ea, xgs };
        
        for (Person p : people)
        {
            p.jump();
        }
//         
//         per.jump();
//         xgs.jump();
//         
//         Person person2 = new ExtremeAthlete();
//         person2.jump();
// 

//         // Will not compile -- incompatible types, a Person
//         // is not necessarily a ShotPutter
//         ShotPutter sp2 = new Person();
    }
}