Virgo 3.6.0.M01 ships with some juicy new features

Virgo 3.6.0.M01 is released and features upgrades to Tomcat (bringing with it web sockets support), Spring, Gemini Web, and Gemini Management.

It includes a completely new admin console with an interesting, minimal architecture which enables it to run on the kernel as well as the Tomcat and Jetty based deliverable. See Christ Frost's blog for more details.

There is also improved Windows support by shortening some of the path names in Virgo's work directory. You can also deploy bundles and WAR files in packed form if you choose to.

The Nano hot deployer also has new support for initial bulk deployment of multiple bundles, particularly useful when they have dependencies between them.

Quite a fun set of features all in all, plus plenty of bug fixes and other improvements.

Please see the release notes for more details or just head over to the milestone download page to get going.

Twelve-Factor Web Apps in Java

A colleague mentioned the Twelve-Factor App site which gives some design guidelines for building web apps. The Dependencies guideline has the following intriguing paragraph:

"A twelve-factor app never relies on implicit existence of system-wide packages. It declares all dependencies, completely and exactly, via a dependency declaration manifest. Furthermore, it uses a dependency isolation tool during execution to ensure that no implicit dependencies “leak in” from the surrounding system. The full and explicit dependency specification is applied uniformly to both production and development."

What would this mean for a Java app? It's more than just using a build tool such as Maven to declare dependencies using explicit coordinates since there is mention of a "dependency isolation tool" at runtime. Well, I think OSGi is the only viable way of implementing this guideline in Java (unless you fancy re-implementing something like the OSGi modularity layer using custom class loaders). The author, Adam Wiggins, makes no mention of OSGi, so presumably he has written Java off as an implementation language. Or does he have some other modularity technology in mind for Java? It would be interesting to know.