Shale began as a proposal for Struts 2.0's migration to JSF, but the Struts community itself never got fully committed to JSF itself which takes a component-based instead of action based approach to web development. Shale thus became a subproject to Struts to provide a JSF alternative, where it has been in develompent for almost 2 years and is now approaching its first stable release.
The discussion on the Struts list began with Don Brown proposing unification: "Struts would be the single framework the world would see. It would contain support for Action-based, JSF-based, and hybrid applications. " Struts & Shale founder Craig McClanahan (who is also the main proponent for Shale) later responded quite bluntly: "the bottom line is that, in 2006, I have philosophical differences with action oriented frameworks (in the sense of what we see available today) as the right long term answer to designing new Java based web applications -- Struts or WebWork or whatever. " Craig went on: "for new developers, I would much prefer to compete with SAF2 than to cooperate with it. If that means a (hopefully amicable) divorce, then so be it."
In response to this, Ted Husted wrote: "If that is the case, then the next question would be whether Shale would be a better fit as a top-level ASF project, a subproject of MyFaces, or somewhere else entirely? " The discussion then had most of the WebWork, Struts, and JSF personalities weigh in with some proposing integration and others suggesting that parting ways while cooperating where it makes sense being the best approach.
The outcome was Shale finally parting ways and becoming it's own project. Shale will no longer benefit from the incredible power of the Struts marketing brand, but the community itself has voted as the Struts community overwhelmingly is in favour of continuing as a modern action oriented framework via migration to WebWork 2.3.
This over all news is good both for Struts and JSF developers, as the industry will not have clarity and also both camps will have greater freedom to evolve separately.
Interestingly, the over all debate possibly revealed some of the fundamental conficts of interest between the java development community and the java vendor community, with Craig himself stating in one post that "Struts Action Framework 2 is a much better (technical) approach to the problems that Struts 1.x targeted," but earlier making the true motivations behind JSF obvious:
I want to focus on attracting a much larger audience of developers who are *not* O-O professionals, whose idea of "code reuse" is cut-n-paste, and who might actually prefer to use tools (SAF2's fundamental architecture is pretty much untoolable, even if someone were motivated to spend the effort to build tooling around it).
Related news: InfoQ.com/jsf