Question

I am implementing a singleton class in Java to make sure no more than one instance of the class is created.

Answer 1

Perhaps the best way is to use an enum with a single instance. This has the added benefit of being serializable and guaranteeing singleton-ness against serialization and reflection, which no “straightforward” Singleton implementation does (private? I have reflection, I scoff derisively at your access modifiers!). It’s also very simple to implement:

public enum Singleton {
    INSTANCE;

    // fields and methods go here
}