What is the necessity of using the Eager Singleton pattern in software development?

The Eager Singleton pattern is used to guarantee the creation of a single instance of a class at application startup, rather than upon first access (unlike the Lazy Singleton).

The necessity of using Eager Singleton is due to:

• Thread safety: the instance is created in advance, which eliminates issues with concurrent creation in a multithreaded environment.
• Implementation simplicity: no synchronization is needed when accessing the instance.
• Guaranteed object availability: the object is available immediately after the program starts.

Example in Java:

public class EagerSingleton {
    private static final EagerSingleton instance = new EagerSingleton();

    private EagerSingleton() {
        // private constructor
    }

    public static EagerSingleton getInstance() {
        return instance;
    }
}

This approach is suitable when object creation is not an expensive operation and it is needed in any case at application startup.