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.

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 The project's home page is http://janino.net

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.

X10 is a type-safe, modern, parallel, distributed object-oriented language intended to be very easily accessible to Java(TM) programmers. It is targeted to future low-end and high-end systems with nodes that are built out of multi-core SMP chips with non-uniform memory hierarchies, and interconnected in scalable cluster configurations. A member of the Partitioned Global Address Space (PGAS) family of languages, X10 highlights the explicit reification of locality in the form of places; lightweight activities embodied in async, future, foreach, and ateach constructs; constructs for termination detection (finish) and phased computation (clocks); the use of lock-free synchronization (atomic blocks); and the manipulation of global arrays and data structures.

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.