Mosaique is a free open source Java tool licensed under the BSD license.
It is a tool to browse a Tiles based JSP inclusion hierarchy in order to understand how pieces fit together. The user interface is available both as Eclipse 3.x plugin and, in a limited edition, also as Swing stand-alone application.
The starting point for browsing are Eclipse projects which contain Struts configuration files declaring the usage of the Tiles plugin. References of Tiles definitions in action mappings' forward attributes can be further drilled down to. The Struts configuration files must reside in the WEB-INF directory of a web application and make references to the Tiles configuration files.
Mosaique helps to gain and maintain control over a complex Struts, Tiles and JSP based web application which makes heavy use of JSP composition from very many small fragments.
Currently, out-of-the-box usage of this plugin requires certain naming and structure conventions for the Eclipse projects, the Struts configs, the action mappings and more which are most likely a show-stopper for most users out there. It is, however, quite easy to make necessary adaptions to Mosaique to support any Tiles project. Do not hesitate to contact the author if you consider to use Mosaique for your project. Support will be given as time permits.
Mosaique is a good complement to Flux, a Struts config generator Eclipse plugin.