Additional Checkstyle checks, that could be added as extension to EclipseCS plugin and maven-checkstyle-plugin, Sonar checkstyle plugin, extension for CheckStyle IDEA plugin.
Here you can find example how to use sevntu-checkstyle-maven-plugin plugin in Maven and Ant projects
Vaadin webapp for displaying Checkstyle Synthax tree (AST) visually in browser.
Maven plugin to create HTML report to show dependecies in DSM view.
Eclipse plugin for displaying Checkstyle Synthax tree (AST) visually
attempt to extend default log4j appenders