Earthly Powers

JavaPolis

Last week i spoke about JAX-RS and Jersey at JavaPolis. The slides are here. Initially i was a bit worried that there were too many slides but i managed to present in 50 minutes with 10 minutes spare that was fully taken up with questions.

Rather embarrassingly i drew a complete blank (and ignored my own general advice on REST that i was imparting!) on one question related to managing users if user information should not be stored as part of session state. Thankfully a JRuby guy in the audience, Ola Bini, came to my rescue and described what Rails does!

A user can have state and thus be a resource that is accessible using a user specific URI. HTTP messages should be stateless so the information declaring the user of each request is supplied by the authentication HTTP request headers. Sounds easy but as i understand it the current Java APIs tend to encourage the developer to use HTTP session state. The area of HTTP authentication and the Java APIs is one that I need to do more research on and then write a blog on the subject as penance!

I enjoyed Martin Odersky's talk on Scala. However, i suspect this is not the right way to present Scala to those who have never seen and/or tried it before. One of my biggest gripes about Scala was the lack of documentation, looks like that has changed with the new Programing in Scala book that is available as an early edition.

Josh Bloch changed his talk and instead presented on the 'Closures Controversy". He was very convincing and i could be persuaded by a sugary syntactical improvement for anonymous inner classes if only because such classes are real pain to write. But Neal provides some counter balance in this blog. Still i don't think the counter balance is enough. Before the conference i was of the opinion that we should leave the Java language alone, not bolt on stuff for which there is an "impedance mismatch", and instead focus resources into improving JVM support for language features, like closures, in Scala, Groozy, JRuby etc. If anything the conference reinforced my opinion.

The OSGi presentation was interesting. Seems like more application servers are adopting the OSGi model and it seems a genuinely useful framework for development, management and versioning of software components for both small and large scale software systems. After this presentation i had some interesting discussions on the topic of the Java language and OSGi. I may well be leaning to the opinion that the work on Java modules and super packages is not necessary and instead the JVM should have an OSGi implementation embedded in it.

Posted at 03:17PM Dec 19, 2007 by Paul Sandoz in REST  |  Comments[2]