Sometimes you use the same images, css and scripts through many webapps and when one of these resources changes you must copy all of these files to each webapp, using weblets you can package all resources in a jar an deploy all common resouces in your webapps in a very elegant way.
How to install?
First of all, you must download weblets from http://weblets.dev.java.net, unzip the file and put weblets-api.jar + weblets-impl.jar in WEB-INF/lib directory of your webapp.
Creating your first resources jar
Please refer to weblets introduction for more details.
Components like sandbox script or tomahawk stylesheet will work with weblets only since Tomahawk / Tomahawk Sandbox version 1.1.4