joeq is a Java 2 (JDK 1.3 and 1.4) compatible virtual machine. It is unique in that it is entirely implemented in Java, leading to greater reliability, portability, maintainability, and efficiency. It is also language-independent, so code from any supported language can be seamlessly compiled, linked, and executed dynamically.
ACDK is a development framework with a similar target of Microsoft's .NET or Sun's ONE platform, but it uses C++ as a core implementation language. It implements the standard library packages, including acdk::lang, acdk::lang::reflect, acdk::util, acdk::io, acdk::text (including regexpr), acdk::net, acdk::sql, acdk::xml, and more. Flexible allocator/garbage collection, threading, and Unicode are implemented in the core of ACDK. Extensions make C++ objects available for reflection, serialization, aspect-oriented class attributes, and [D]ynamic [M] ethod [I]nvocation. This DMI acts as an universal object oriented call interface to connect C++ with scripting languages (Java, Perl, Tcl, Python, Lisp, Visual Basic, and VBScript) and standard component technologies (CORBA and COM).
SuperWaba is a VM for PDAs. Because of the way it was written, you can use Java to develop programs for it. It supports exceptions, threads, many user interface controls, double and long 64-bit types, grayscale, color, 3D controls, and JNI and Java libraries, among other features. The project has been superseded and replaced with TotalCross.
WebComp is a tool for using scripting to compose and configure Web sites from various existing components, such as static HTML, Java Servlets, Java server pages, and others. It includes a scripting language, a component model/framework, and a set of basic pluggable components to use with it. It is based on Java Servlets.
FrAid (Fr[actal] Aid) is a programming language that is appropriate for mathematical computations, visualization, batch processing, and more. It features both a standalone application that provides a programming environment for the language and a system for integrating the language with Java. The Java interface allows mathematical equations and formulas to be used with Java code, making it easier to process numerical computations, symbolic computations, imaging, CAD, and more.
Kanaputs is an interpreter for Java. It runs Java code without compilation, as each instruction is executed when you write it. Kanaputs can be embedded very easily into an XML document to add programmatic features. For example, Kanaputs is fully integrated with Ant and provides a way to execute Java within an XML Ant build file. The grammar of the Kanaputs language is very close to the Java grammar but adds some flexible features such as typeless variables and reactive variables.
Groovy is an agile, dynamic language for the JVM which combines many features from languages like Python, Ruby, and Smalltalk and makes them available to Java developers using a Java-like syntax. It is designed to help get things done on the Java platform in a quicker, more concise, and fun way. It can be used as an alternative compiler to javac to generate standard Java bytecode to be used by any Java project or it can be used dynamically as an alternative language, such as for scripting Java objects, templating, or writing unit test cases.