JavaでgetClass（）メソッドを使用できるのはいつですか？

class User {
   private int id;
   private String name;
   public User(int id, String name) {
      this.id = id;
      this.name = name;
   }
}
class SpecificUser extends User {
   private String specificId;
   public SpecificUser(String specificId, int id, String name) {
      super(id, name);
      this.specificId = specificId;
   }
}
public class TestUser {
   public static void main(String[] args){
      User user = new User(115, "Raja");
      SpecificUser specificUser = new SpecificUser("AAA", 120, "Adithya");
      User anotherSpecificUser = new SpecificUser("BBB", 125, "Jai");

      System.out.println(user.getClass());
      System.out.println(specificUser.getClass());
      System.out.println(anotherSpecificUser.getClass());
   }
}

出力

class User
class SpecificUser
class SpecificUser