Mark Ramm-Christensen posed some questions about using the JVM as a platform for dynamic languages. Many people do, in fact, use dynamic languages on the JVM (Groovy, Beanshell, Rhino, Jython, JRuby are some big ones… and don’t forget Scala, Nice and other “non-dynamic” languages that target the JVM). But Java the platform has not gotten widespread or serious attention until recently (witness the recent resurgence of Jython, the rise of JRuby and the coming of the Da Vinci Machine).
[From Why Java remains the most popular language on the JVM]

Answering the question “Why Java remains the most popular language on the JVM” gives clues as to what might be the next most popular language on that platform.