Java yields to other languages on the Java Virtual Machine

Groovy. Another language for the JVM is Groovy, which has a mixed reputation among developers. Billed as "an agile dynamic language for the JVM," Groovy builds on Java strengths while also offering features inspired by languages such as Ruby and SmallTalk, says the Groovy Web page on Codehaus.

"It's definitely easier to program," with Groovy than Java, says Jon Travis, principal software engineer at SpringSource, which oversees development of the Groovy language. "Groovy all around adds a lot of expressiveness for people who are very familiar with Java," he notes.

PHP so far not catching on among JVM developers While Ruby and Python implementations have gained a foothold on the JVM, the same oddly is not true for the popular PHP language, says Sun's Bray. "The No. 1 candidate that people are working [on] but isn't really there yet in terms of widespread adoption is PHP," he notes.