If you are interested in Scala, make sure you watch this interview with Martin Odersky, the key designer of the language.
In case you don't know Scala yet:
- It's a fusion of functional programming and object-orientation, taking the very best of both worlds.
- It compiles to Java byte code and .NET IL code, so you can mix Scala with your existing Java or .NET libraries. Java support appears to be slightly better.
- Plugins for Eclipse and Netbeans are being worked on but of course they are not yet as mature as JDT.
- The first Scala book just came out.
- The Scala documentation that comes with the download is very good. I recommend to work through "ScalaByExample.pdf" to get a grasp of the language.
- Scala provides strong advanced concepts for concurrent programming, "Actors" for example.
From what I can see, the Scala crew is doing a brilliant job at designing the language.
I can see Scala superseding Java as the most popular programming language.
(...and of course, Scala and db4o play together very nicely in case you ever want to store objects or query for them...)