downcasting

CurrentUser.java

class CurrentUser extends User {
  public String who() {
    return "who - CurrentUser class!";
  }
}

Main.java

class Main {

  public static void main(String[] args) {
    User user = new CurrentUser();
    CurrentUser currentUser = (CurrentUser) user;
    System.out.println(currentUser.who());
  }
}

User.java

class User {
  public String who() {
    return "who - User class!";
  }
}