WebJars is an easy way for server-side developers (such as your humble servant) to manage client-side resources such as Bootstrap, jQuery and their like, within the same package management tool they use for their server-side libraries. In essence, what WebJars does is package a set version of the client-side resource (CSS or JavaScript) in the META-INF/resources of a JAR and upload it on Maven Central. Then, any Java EE compatible web-container makes the resource available under a static URL.

People who know me also know I’ve interest in the GUI: that means I’ve sometimes to get my hands dirty and dig deep into stylesheets (even though I’ve no graphical skill whatsoever). When it happens, I’ve always questions regarding how to best factorize styles. In this regard, the different CSS versions are lacking, because they were not meant to be managed by engineers.