The WebClient API specification has been released on the Mozilla site. From the introduction:
The webclient project aims to provide a browser neutral Java API that enables generic web browsing capability. This capability includes, but is not limited to: web content rendering, navigation, a history mechanism, and progress notification. The actual capabilities implemented depend on the underlying browser implementation. Webclient does not deal with web authoring.Something like this can't come too soon with the number of Java web browser projects out there. It should be worth submitting it to Sun's JCP as well.