Enum as immutable java objects.

enum_trick.java

package com.codlex.deximat.raf.third_year.web_programming.exam.project.part2.messages;

public enum CancelReservationResponse {
	PASSENGER_DOESNT_EXIST("Reservation cancellation unssuccesful selected passinger doesn't exist."),
	FLIGHT_DOESNT_EXIST("Reservation cancellation unssuccesful selected flight doesn't exist."),
	RESERVATION_NOT_POSSIBLE_TOO_LATE("Reservations can't be canceled if flight is within next 24 hours."),
	SUCCESS(null),
	WRONG_FLIGHT("Reservation cancellation unssuccesful selected passinger isn't on flight.");

	private String description;

	private CancelReservationResponse(String description) {
		this.description = description;
	}
	
	public String getDescription() {
		return this.description;
	}
}