Jacclog is a modular open source access logs analytics system written in Java.
LogKit.Net is an easy to use, functional error logger for .Net. It a fully managed C# port of the popular Apache Jakarta LogKit for java.
Open Source Application Server Appliance based on Open Source GlassFish
This is a port to Qt/C++ of the Jakarta project's excellent log4j package. Qt users can now benefit from a logging package that can be configured at run-time, thus minimizing (and ideally, eliminating) recompilation.
RDFStore is a C/Perl library to parse, store and manage RDF.