Jun 3, 2009

Report from Presentation at JavaForum in Malmö and Gothenburg

Last week I did present Microlog at JavaForum both in Malmö and Gothenburg. JavaForum is the Swedish JUG. It was a great honor to be invited to both these places. These are my reflections and thoughts about my presentation.

At the first presentation in Malmö there was around 50-60 people. I knew many of the people beforehand, which made me less nervous. The presentation went smoothly and I got some questions, that hinted me what to improve in the presentation. Unfortunately I did not had time to stay afterwards to get some more feedback.

Driving to the destination in Gothenburg at rush hours was not an easy task. My GPS device was out of battery, so I used Google Maps to find my directions. When no GPS device is attached, it uses GSM cells to figure out where you are. The accuracy is about 600 m in a city like Gothenburg. That is maybe enough when walking in a city to find out where to go, but by car that is not enough. What a shame I was not in a Hollywood movie, where the accuracy seems to much better than that. Anyway I found the place to be and was there on time.

Afterwards I had the opportunity to speak to some people in the audience. First of all I got a question about what Maven help I wanted. It is mainly about getting Maven to generate better packages for the releases. For more details see this discussion.

One other question I got, was "What is the reason for not being able to do printStackTrace() and re-direct it to a log? Or do you have any idea how to solve it?". The thing is that I have not found a way to re-direct to another destination within Java ME. The reasons are:
  1. The System.err is final in the System class found in Java ME (CLDC). I do not know why this is, but it hinders you as a developer from setting these to something like a FileOutputStream or similar.
  2. The method printStackTrace() comes in different flavors in Java SE. For example, the public void printStackTrace(PrintStream s) is useful to direct the stack trace to another destination than the default one. This is not available in Java
One workaround that works under some condition is to re-direct the output from your Java MIDlet outside the JVM found in your phone. On the Symbian platform there are such applications available. If the problem is reproducible in the WTK, you could run it look you normally do. By using the ConsoleAppender you get both the normal exception message along with the stack trace. BTW do you know any other workaround? If yes, please enlighten me.
That is all for now. Thanks to Björn Granvik and Rickard Thulin for inviting me to JavaForum.


Thiago Bruno Melo de Sales said...

Congratulations for the Microlog project. It has helped me a lot! Could u please tell me if I can find any available Microlog tutorial? (examplaining in a deeper details its main features and how to use them).


My Open Source Software Development Blog said...


there is a quick start guide here


There is also a lot of example midlets found in the download pages.