New Year starts with Scala

Slowly up to speed

New Year is here, smoke calming down after a couple of nights of excessess with fireworks (and some other stuff too).

I think tonight, the sky will be clear, and the air fresh again.

After lazying around with my family during the Christmas Break, its time to actually work again.

Preparing lecture for  JG.DKs annual conference

I am preparing my lecture for the Danish Java Groups Annual Conference, it will be held at Hindsgavl Castle on my Island (=Funen) in Denmark. The program is here.

My talk will be about a new language – Scala – which is bytecode compactible with Java, and runs smoothly on the JVM. I claim that Scala is going to give us back Object Oriented progamming – without having to do some of the awkward workarounds, that java is forcing us to do.

Out of the host of new languages that run on the JVM, like JRuby, Groovy and Jython – I really think Scala stands out.

What is so special about Scala?

It is a functional language. It is an object oriented language. It is a type strong language – exactly like Java.

It has traits – an ability to add methods to an interface – a language feature that we have been missing since

It is pure and well designed. Invented by Martin Odersky – who designed the Java generics.

Eventually, Java 7 or 8 will be patched with closures, and traits. But those will be patches. I am right now reading a book by Odersky, Spoon and Venners – Programming in Scala – highly recommendable.

Your hello world in Scala


Lets try Scala out.

First, lets get the convenient Eclipse plugin (you need Eclipse 3.4 + to make it work) from its update site:

Select New>Scala Project.

This gives you a … Scala project.

Now in the src folder, add a Scala Application (runnable):package application

object HelloWorld extends Application with FirstTrait{
override def main(args: Array[String]) {
println(“Hello, world from Scala!”)
println(“From trait ” + greet(“world”))
print(arg+” “)


Make your first trait:package application

trait FirstTrait {

def greet(name:String):String = “Hello “+name


Run the application (Run > Scala Application), to see the output:

Hello, world from Scala!
Now – hello from trait Hello world

Thats it – hello world in Scala.

Hello World in Scala

Screenshot from Eclipse: Hello World in Scala

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