Groovy is an agile dynamic language for the Java Platform with many features that inspired languages like Python, Ruby and Smalltalk, making them available to Java developers using a Java-like syntax.

Boo is a new object oriented statically typed programming language for the Common Language Infrastructure with a python inspired syntax and a special focus on language and compiler extensibility.

Janino is a compiler that reads a Java expression, block, class body, source file or a set of source files, and generates Java bytecode that is loaded and executed directly. Janino is not intended to be a development tool, but an embedded compiler for run-time compilation purposes, e.g. expression evaluators or "server pages" engines like JSP. Janino can also be used for static code analysis

Ruby extension providing bindings back to an in-processes hosted JVM. Java classes are exposed through Ruby semantics.

JRuby is an alternate implementation of the Ruby programming language.

MVEL is the MVFLEX Expression Language, a general purpose expression language.