OVal – object validation framework

OVal is an extensible object validation framework for Java 5 or later. Annotations (@NotNull) or XML configuration files can be used to express class constraints. OVal can optionally use AspectJ to enforce automatic validation (DbC)

How to use: http://oval.sourceforge.net/userguide.html

OVal is in the central maven repository:

net.sf.oval
oval
1.87

Today’s small-to-medium-sized (SMB) businesses and large enterprises are saving on their monthly communications costs by making one simple decision: to switch to a VoIP service solution from their old, outdated Plain Old Telephone Service (POTS). By choosing a new VoIP service, these companies enjoy the flexibility, reliability, call features, and audio quality that only a VoIP service can provide. Plus, they cut their phone bill by up to 70%!