In Relation To

Hibernate Tools 3.1.0.beta5 (http://tools.hibernate.org) have been made available.

I, for one, welcome our new penguin overlords.

Recently, Simon Brown put together a set of requirements for a very simple blogger application that could be used to compare Java web frameworks. I have my reservations about the actual requirememts he put together (in particular, there is no form submission!) but since some other framework authors have bitten, I've gone ahead and ported the example to Seam. I want to put a massive caveat around this post: Seam is absolutely not designed for applications like blogs or web forums; these kind of problems are very easy to solve using something like PHP or Ruby on Rails and there is no really good reason to use Java for a problem like this (unless Java is all you know). We have a set of requirements here with /no conversations/ and /no business processes/, so all the sophisticated state management machinery of Seam is redundant. Nevertheless, frameworks need to make simple things easy, and you'll see how little Java code we need to write to solve this simple problem using Seam.

People using the Criteria API have either transparently or knowingly used a ResultTransformer . A ResultTransformer is a nice and simple interface that allows you to transform any Criteria result element. E.g. you can make any Criteria result be returned as a java.util.Map or as a non-entity Bean.

Moving Hibernate source code to our new Subversion home is done. Both developer and annonymous access have been set up. Currently, web access is only available via the Apache module which is less than ideal. We have been told that either Fisheye or ViewCVS access over the Subversion repsoitory will be setup soon.

A bug report was recently opened in Hibernate's JIRA stating that Hibernate incorrectly handles deadlock scenarios. The basis for the report was an example in the /Pro Hibernate 3/ book (Chapter 9). For those perhaps not familiar with the term deadlock, the basic gist is that two processes each hold resource locks that the other needs to complete processing. While this phenomena is not restricted to databases, in database terms the idea is that the first process (P1) holds a write lock on a given row (R1) while the second process (P2) holds a write lock on another row (R2). Now, to complete its processing P1 needs to acquire a write lock on R2, but cannot do so because P2 already holds its write lock. Conversely, P2 needs to acquire a write lock on R1 in order to complete its processing, but cannot because P1 already holds its write lock. So neither P1 nor P2 can complete its processing because each is indefinitely waiting on the other to release the needed lock, which neither can do until its processing is complete. The two processes are said to be deadlocked in this situation.

I'll be demo'ing Hibernate Tools at EclipseCon on March 21st. See details here .

Thomas has posted a movie demonstrating the use of Hibernate Tools (part of JBoss IDE) to reverse engineer an entire runnable Seam application from an existing database.

Seam 1.0 beta 2 has been released:

I have been fed up with Velocity ís ability to ignore and even hide errors and exceptions occurring in the templates used in Hibernate Tools .