Person/Teacher/Student (Example)

public abstract class Person {
  final String id;
  final String name;

  private String info = "I'm a  " + this.getClass().getSimpleName() + ". My ID is " + this.id
      + " and my name is " + this.name;

  public Person(String id, String name) {
    this.id = id;
    this.name = name;
  }

  public String getInfo() {
    return this.info;
  }
}

public final class Teacher extends Person {
  public Teacher(String id, String name) {
    super(id, name);
  }
}

public final class Student extends Person {
  public Student(String id, String name) {
    super(id, name);
  }
}