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.
Depending on what you want to do, many of the uses of semaphores are easier to implement in Java using the synchronized keyword. If you're already ruled that out for your application, then by all means use Doug Lea's libraries, which offer a far wider assortment of control mechanisms.