Scala Training at JetBrains: How It Was

On September 14, 2013, a free one-day training course on the Scala language was held at JetBrains St. Petersburg office.

The training was conducted by Alexander Alefas Podkhalyuzin , the developer of the Scala support plugin in IntelliJ IDEA. During the day, he conducted an introductory practical course on Scala, classes were held from 12:00 to 19:00. The course was designed for beginners (or willing to start), but all participants had to have experience developing in Java.

We arranged the training in order to remind that there is an alternative for Java. The developer subconsciously wants to be pushed in a new direction: something needs to be developed, but there is no time, and in general, I want to sleep. So, the training should have been a catalyst for the development of those who came, and at the same time to help decide whether Scala is suitable for solving their problems.

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27 people came (enrolled 40). This is an excellent result for a free event: on average in Russia half comes. Reached the end of 18.

Among the participants were:
three come from Habr;
two girls (by the way, drop rate among girls - 0%, i.e. all who signed up, came);
at least 7% of students.

The training consisted of three parts. At the end of the first and second it was necessary to solve a practical task (on Scala, of course). The first - introductory part was the largest - 2.5 hours.

People coped with tasks in different ways. For example, one of the tasks was the implementation of quick sort on Scala. Mostly people wrote the same way as if they were writing in Java. One person wrote what was expected:

def qsort(m: Array[Int]): Array[Int] = if (m.length < 2) m else { val pivot = m(m.length / 2) qsort(m.filter(pivot > _)) ++ (m.filter(pivot == _)) ++ qsort(m.filter(pivot < _)) } 

We hoped that the people would actively ask questions, but the load of new knowledge was so heavy that they asked questions sluggishly. Had to announce lunch. After immersing in the tongue, the tea and coffee cakes went off with a bang, and the second part of the training on a full stomach digested, of course, more difficult.

First, the blood, as it should be after dinner, was poured from the brain and rushed to the stomach, and secondly (it seems to us that this was the main reason) the material was objectively more difficult: we studied implicits in Scala. There were even fewer questions (well, that was asked at all).

Some practical tasks were ingenuously (see slides ). Nobody coped with them. Next time, we will ask you not to turn off your wit when entering the office.



More than half of those who survived the training until the end said they were interested in Scala. In fact, if someone has firmly decided that Scala is no good for him, this is also good, because a conscious choice of a tool is right.

Alexander Podkhalyuzin, who conducted the training, was pleased that he had managed to tell quite a bit about Scala. However, this is an unobvious plus: maybe one of the participants has reached the limit of perception of the new, and if the training were two or three days, it would be more effective, but it is more difficult to go for a long training, and even more so to do homework.

Dialogue on the sidelines:

- I understood 30 percent.
- Oh you cool! You still understand a lot!

Hopefully, the training day was the birthday of new projects on Scala in St. Petersburg.