Prevalence Systems article on devWorks

"Persisting state and data has always been a problem with object-oriented software. Over the years, developers have stored object data in many ways, including relational databases, flat files,and XML. None of these approaches really managed to keep the software purely object-oriented. The Prevayler team is changing this with the object prevalence concept. This article introduces object prevalence."

http://www-106.ibm.com/developerworks/java/library/wa-objprev/?dwzone=java