public class LibraryUser implements java.io.Serializable {

   private Long id;
   private Long version;
   private String cardKey;
   private String unifiedKey;
   private Date admissionDate;
   private Date expiryDate;
   private Set reservations = new HashSet();
   private Set libraryUserTypes = new HashSet();
   private Set borrows = new HashSet();
   private Set libraryUserBlocks = new HashSet();
   private Set libraryUserFines = new HashSet();

   // ************** flag or state-info ****************
   private boolean dateExpired;
   
   /** default constructor */
   public LibraryUser() {
   }

   /** constructor with id */
   public LibraryUser(Long id) {
      this.id = id;
   }

   /******* my constructor with aGiveDate ******/
   public LibraryUser(Date aGiveDate) {
      this.dateExpired = isDateExpired(Date aGivenDate);
   }
...

   public boolean isDateExpired(Date aGivenDate) {

      if (this.expiryDate.before(aGivenDate))
         return true;

      return false;

   }

}

public class Borrow  implements java.io.Serializable {

     private Long id;
     private Long version;
     private Date borrowDate;
     private Date dueDate;
     private Date returnDate;
     private Date reportlostDate;
     private Date paidDate;
     private int renewedNo;
     private LibraryUserType libraryUserType;
     private Item item;
     private LibraryUser libraryUser;
     private Set libraryUserFines = new HashSet();

     // ************** flag or state-info ****************
     private boolean overDue;
     private Integer daysOfOverDue;
     private BigDecimal fineAmount;

    /** default constructor */
    public Borrow() {
    }
   
    /** constructor with id */
    public Borrow(Long id) {
        this.id = id;
    }
   
    /** constructor with aGivenDate */   
    public Borrow(Date aGivenDate){
        setOverDue(isOverDue(aGivenDate));
       setDaysOfOverDue(calculateDaysOfOverDue(aGivenDate));
       setFineAmount(calculateFineAmount());      
    }
...

}

public Object instantiate( String entityName, EntityMode entityMode, Serializable id ) {
..... Date now = new Date();
}