Singleton in Java

Singleton

//OPTION 1 using enums
//Each element in the enum is unique and keep their last modified values
//even when used by threads the values of the elements are the same
//they can be accessed via Currentcy.DIME and so
//everytime you instance class Animal, the values keep the last state they were
public enum Animal {
  CAT("meow"), DOG("bark"), ELEPHANT("WTF"), HUMAN("talk");
}


//OPTION2 using static/synchronized
//Everytime you call the getInstance method you'll get the last state of the Animal class
//Only the first time, you'll get a brand new Animal class 
//The latter times you call it, it will keep tha last state of the instance
public class Animal {
  private static Animal uniqInstance;

  private Animal() {
  }

  public static synchronized Animal getInstance() {
    if (uniqInstance == null) {
      uniqInstance = new Animal();
    }
    return uniqInstance;
  }
}