Starting with version 2.7.2, Scala added an experimental feature (which will no longer be experimental as of 2.8.0) called Manifests that allow you to selective

Starting with version 2.7.2, Scala added an experimental feature (which will no longer be experimental as of 2.8.0) called Manifests that allow you to selectively reify erased types. See this blog post for more: http://www.scala-blogs.org/2008/10/manifests-reified-types.html http://www.scala-blogs.org/2008/10/manifests-reified-types.h... This, combined with specialization (compiling primitive-specialized versions of code with generic types to improve performance of, for example, using function types on primitive collections) will make it easier to write performant, numeric code in Scala than in any other JVM language (up to the limits of the JVM, of course). The NLP communities at Stanford and Berkeley, which do a fair amount of machine learning, have a long history of working in Java (http://nlp.stanford.edu/software/ http://nlp.stanford.edu/software/, http://nlp.cs.berkeley.edu/Main.html#Software http://nlp.cs.berkeley.edu/Main.html#Software) and have recently started using Scala as well (http://www.scalanlp.org/ http://www.scalanlp.org/). Scala's interface with Java collections IS a bit clunky. Thankfully, this is a library issue, not a language issue, and can be solved with better libraries. See http://github.com/jorgeortiz85/scala-javautils http://github.com/jorgeortiz85/scala-javautils (for Scala 2.7.x) and http://github.com/scalaj/scalaj-collection http://github.com/scalaj/scalaj-collection (for Scala 2.8.x).