public class State {   
  // Attribute Data members   
  private String stateCode;   
  private String stateName;
  private String nickname;
  private int population;    
  // Relationship Data Members
  // Capital city
  private City capitalCity;
  // Set of cities   
  private Vector<City> cities;
}

public class City {
  // Attribute Data members
  private String cityCode;
  private String cityName;
  // Relationship Data Members
  // State city lelongs to
  private State state;
}