public static void main(String[] args) { Soldier sanmao = new Soldier(); AbstractGun gun = new Handgun(); sanmao.setGun(gun); sanmao.killEnemy(); gun = new Rifle(); sanmao.setGun(gun); sanmao.killEnemy(); gun = new MachineGun(); sanmao.setGun(gun); sanmao.killEnemy(); }