Suppose you have several applications which share the same code and most of the other resources, but have a somewhat different look and feel, some labels change, etc. (thin
If you don't want to go the EAR route, using tomcat, etc; there are a few other ways to achieve the consistency you want.
If you want to share just js and css, look into pack:tag. You could host the .js and css from an apache server, set up your httpd.conf so your webapps can call it, then use pack:tag from your application wars - DRY and compression in one step.