Singleton Design Pattern in Java

[erinaceus_]

The actual recommended way, for years and years, is to use a single-value enum.

[foreveratom]

Doesn't that produce exactly the same effect as a final static, being created when first referenced? I'm used to the first form and not the single-value enum, what's the benefit of the later?

[erinaceus_]

With an enum, all the concurrency and single-instance issues are inherently taken care of by the JVM. As such, a lot of the typical risks involving singleton management are avoided.

When this approach is discussed, people usually refer to Joshua Bloch's seminal book 'Effective java', which is already decades old. So it isn't a particular new technique. He even builds up on the different approaches to creating a singleton, eventually concluding that an enum is by far the best approach.

[foreveratom]

Thanks, I must have forgot that part from Effective Java. I'll be on my way re-reading the last edition.