As the name already indicates, SimpleLog represents a really simple logging utility which can be used in your "homemade" Java application. I created the "library" (it's really a big name for this app) during another project I was developing because I didn't want to use Log4J.
What's different?
SimpleLog has the advantage that it produces you a nicely formatted output. All the logs are written as XML file and could therefore theoretically be used as input for 3rd-party applications for being further processed. Moreover an appropriate XSL file is created and directly linked with the XML log file such that a nicely formatted HTML output page is created.