This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
For the singleton idea, see this article. However, be aware of the limitations of this approach. If you need the singleton value to be clusterable, then you should look at the Distributed Cache approach described in my article in this month's JavaRanch Journal. Kyle
What you are actually trying to accomplish with the singleton? Do you really need a singleton or are you just trying to apply a "design pattern". I don't know your domain, but based on my experience, I'd say there's a 99% chance you don't actually need the singleton. You'll save yourself a lot of trouble but not chasing after an anti-pattern. Instead, look at the qualities of the singleton you are really interested in (controlled instantiation, caching, etc...) and pick a solution that gives you those. (just a suggestion)