How to Implement the Singleton Pattern using Enum in Java

How can I implement the Singleton Pattern using an Enum in Java?

public enum Singleton {
    INSTANCE;

    // Method to perform some action
    public void doSomething() {
        // Implementation here
    }
}

The Singleton Pattern ensures that a class has only one instance and provides a global point of access to it. In Java, one of the most effective and simplest ways to implement this pattern is through an Enum. This approach automatically handles serialization and guarantees thread safety, making it a preferred solution.

public enum Singleton {
    INSTANCE;

    public void doSomething() {
        System.out.println("Doing something...");
    }
}

Causes

• To limit the instantiation of a class to only one object.
• To provide a global access point to that instance.

Solutions

• Define an enum with a single element for the singleton instance.
• Include any methods or fields you want the singleton to have.

Mistake: Not using the Enum singleton correctly, such as accessing it without calling the INSTANCE.

Solution: Always access the singleton instance using Singleton.INSTANCE.

Mistake: Confusing the Enum-based singleton with other designs leading to improper usage.

Solution: Understand that Enum implements Singleton inherently and should be used as is.