Wednesday, May 16, 2007

JavaOne 2007

All of last week I was at JavaOne. It was an exhausting but very interesting week. Like last year, there were many interesting sessions, too many to list them here. Let me just mention the one I enjoyed most was the one by Neal Gafter on Closures for the Java Programming Language (BOF-2358). I can't wait until they're in the Java language!

Not only did I attend sessions and BOFs, I also presented BOFs. Three of them to be precise. I recorded the audio on my MP3 player. Unfortunately the quality of the audio is pretty bad. I'm posting the audio recordings below. I'm also posting the slides. Here they are:

BOF8847: Developing Components for Java Business Integration: Binding Components and Service Engines

Presented by Frank Kieviet, Alex Fung, Sherry Weng, and Srinivasan Chikkala
Attendance: about 100

You cannot cover how to write JBI components in just 45 minutes. We were also not sure about what the audience was interested in. That's why we assumed that the audience would consist mostly of people who have never written a JBI component before, and are relatively new to JBI. That's why we decided to talk mostly about general information on JBI and JBI components, and highlight the power of JBI and discuss how to go about developing one.

As an experiment I wanted to try a new format (at least new for me): rather than slicing up the session into four parts of 10 minutes, we cast the session into a "discussion forum". Of course the questions and answers (and even the jokes) were well rehearsed.

Unfortunately, the audio/visual people that control the meeting rooms, had forgotten to start the session timer. As a result the audio was cut unexpectedly just a minute before we could finish up.

Nevertheless, I think it was an interesting session.

Presentation JavaOne07-BOF8847 (pdf)

Audio JavaOne07-BOF8847 (mp3)

BOF8745: Leveraging Java EE in JBI and vice versa

Presented by Frank Kieviet and Bhavanishankara Sapaliga
Attendance: about 60

This BOF was originally to be presented by Vikas Awasthi and Bhavanishankara Sapaliga, but Vikas couldn't make it, so I replaced him. We focused the session on how JBI and EE can play together, trying to make it interesting for both JBI application developers as well as for EE developers. At the end I ran a demo with NetBeans showing three different scenarios. The demo-gods were with me: the demo went very smoothly. Unfortunately I forgot to demo how to add an EJB to a composite application. Another valuable lesson learned.

Presentation JavaOne07-BOF8745 (pdf)

Audio JavaOne07-BOF8745 (mp3)

BOF9982: The java.lang.OutOfMemoryError: PermGen Space error demystified

Presented by Edward Chou and Frank Kieviet
Attendance: about 116

This session was on Thursday night at 10pm. That night was the JavaOne After dark bash. Free beers, music and snacks for everyone. Therefore we didn't expect much of an attendance: memory leaks are a rather dry subject, and why leave the party early to go to this session? Also, some of our thunder had been stolen by SAP who demo-ed a tool to track memory leaks in a morning-session earlier that week. So we were quite surprised when about 116 people turned up for our session. Most stayed until the very end, and there were also quite a few interesting questions. Apparently a lot of people struggle with memory leaks in permgen space -- in my presentation I mention that I get about a hundred hits on my blog every day from people who search for this memory exception in Google.

Presentation JavaOne07-BOF9982 (pdf)

Audio JavaOne07-BOF9982 (mp3)

Tuesday, May 1, 2007

JavaOne / memory leaks revisited...

Memory leaks in print 

A few months ago, Gregg Sporar together with A. Sundararajan started an article on memory leaks in the magazine Software Test & Performance. While writing that, he stumbled upon my blog and decided to cover the "java.lang.OutOfMemoryError: PermGen space" exception too. I offered to collaborate on the article. The article eventually grew so much it was split in two. Part one was published a month ago. Yesterday, part two was published.

Memory leaks at JavaOne

Edward Chou submitted a proposal for a BOF at JavaOne 2007. He and I will be presenting a BOF on the "java.lang.OutOfMemoryError: PermGen space" exception. I'll try to record the session with my MP3 player and post it on my blog.

In preparation for our presentation, we've been looking at some real-life examples of permgen memory leaks. We took a few memory dumps that came from actual customers in actual production environments. We discovered a few more improvements we could make to jhat: it was already fairly simple to track the leaks with jhat; with these changes it becomes really simple. We were actually quite surprised how simple. More on that in a future entry, either on my blog or on Edward's.

More at JavaOne

Speaking about JavaOne... I have my hands full. Next to the memory leaks BOF, I'm also presenting a BOF on JBI ("How to develop JBI components") and I'll be co-presenting another BOF on "EE and JBI."