A Look at the Main JVM Languages Today, February 14, 2012 The JVM hosts an increasingly wide array of languages. Here we compare the prominent ones, mourn those that have come and gone, and celebrate newborn languages clamoring for attention.
Scala attempts to cross or blend the OO and functional paradigms. Its fundamental syntax can be used as a straight replacement for Java, or the more advanced features can be employed to write functional code. The result is that it's easy to migrate from one paradigm to the other as skills improve. (Functional is the preferred style of advanced Scala developers.) The downside of this approach is that code can be hard to read due to the linguistic gap between beginners and experts. The language has a built-in Scala library, which solves many of the parallel programming woes facing traditional developers. Drawbacks of the language, other than the occasional obscurity of the code, include a compiler that is very slow by comparison with most of the other languages detailed here, and a history of new releases that break binary compatibility with previous releases.
A recent interview with Martin Odersky, the language's creator, gives his thoughts on some of those issues.