Prime numbers (in Ruby)

For me it is like back to the basics. Back to the roots. Eratosthenes sieve. I remember when I implemented this algorithm for the first time. It was in a high school and I was feeling like doing a rocket science. Today I would like to look at the algorithm once again but from Ruby perspective.

Java synchronizers - Semaphore

It has been a while since I wrote post about CountDownLatch. Over two months actually but it doesn’t mean I forget that I promised to write about the other synchronizers. So to not speak idly today I'm going to write about Semaphore class.

Lightning talks at Wroclaw JUG

Last Tuesday Wroclaw JUG has organized for the first time lightning talks meeting. I had a pleasure to be one of the speakers and from my point of view the whole event went very well.

Approaches to testing

I have learned testing in the hard way. To be honest my first tests probably didn't test anything. Unfortunately there was no one around me who could help me with it so I was on my own. After few weeks I was able to write unit tests that actually check behaviour of my classes. Green bar really made me proud. However my unit tests at this point were really complex and hard to maintain. I knew that something is missing in my tests and I need to learn more. It was few years ago. Today I know way more about testing but I'm still learning. My latest lesson comes from Oredev Conference.

Java synchronizers - Countdownlatch

Package java.concurrency contains many high level APIs for working with concurrency. It has been added to JDK in version 5. It's quite long time ago. However many developers still use raw Thread and synchronization. I'm pretty sure it is not because they like it but more likely they don't know what kind of goodies they have at their disposal. So in order to spread the word I would like to present Java synchronizers and how to work with them.