December 12, 2010

Scala for the busy Java developer

The title of this blog entry is shamelessly inspired on "The busy Java developer's guide for Scala" from Ted Neward. As a busy man myself and having a Java background with interests in Scala, I went looking for sites, books, exercises, tools, etc... to quickly learn the ins and outs of Scala.

There is of course the main site (, with references to some good books, but that simply takes too much time. A good traject to follow and which I followed also, is the one I describe below.

First thing you need is of course a Scala compiler/interpreter. Why bothering installing Scala on your local machine, even if you have already a good IDE installed. It is far easier to start with an online interpreter (, which simply runs in a browser. It does not run on my iPhone (still iOS 3.1.2, I know,...). Maybe it works on a later version -if so, then probably also on an iPad- or on an Android phone or tablet,... Anyone?

Although that same site has some tutorials on it also, they are not sufficient for a real introduction to the Scala languate. For Java developers, there is a much better introduction from Ted Neward on IBM developerWorks. Here is the deeplink with an overview of all the Scala articles from Ted on developerWorks, sorted by date:

It is very easy to execute the code from the articles inside de interpreter on Simply Scala, just do a copy & paste. When Ted actually implements a runnable application, skip the object definition and execute the body directly in the interpreter. For example in the article "Class Action", he uses the following snippet to exercise the Rational class:

object RunRational extends Application
  val r1 = new Rational(1, 3)
  val r2 = new Rational(2, 5)
  val r3 = r1 - r2
  val r4 = r1 + r2
  Console.println("r1 = " + r1)
  Console.println("r2 = " + r2)
  Console.println("r3 = r1 - r2 = " + r3)
  Console.println("r4 = r1 + r2 = " + r4)

Just copy anything within the brackets ( {...} ) into the interpreter et voilà... 

Now that you have a good start and if you have some time left, there are a lot of interesting exercises on the internet to enhance your skills (especially the functional part, which is new for Java developers). Project Euler ( and Rosetta Code ( contain quite some interesting and challenging exercises which are also used at universities as small projects.

Have fun with Scala! It might be the language of the future on the JVM, time will tell...

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