Mario Gleichmann has started a great series of blog post about functional programming in general using Scala examples in particular. Check it out, if you are interested in the concepts of functional programming, especially if you are coming from imperative programming style with object oriented languages. It’s a kind of smooth introduction to functional programming Java developers need.
You will also find some ideas for ordinary Java programming if you are not a new language hopper. This series will be continued, here are links to the first four articles.