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.
If you are using EclipseLink, you can set the persistence unit property "eclipselink.persistencexml" to give the path to the file. You can either pass this property in your properties Map, or set it as a system property.