This week's book giveaway is in the Agile and Other Processes forum. We're giving away four copies of The Little Book of Impediments (e-book only) and have Tom Perry on-line! See this thread for details.
A nice thing about defining your datasource in Spring's application context is being able to pull values from properties files. I can then do something like set an environment variable and use that in the app context to tell spring which properties file to load (dev/stage/prod/whatever) and I'd pull the correct database info.
What is the appropriate way to handle this without Spring and using persistence.xml for all your JPA configuration?