JAsCo is an aspect-oriented programming (AOP or AOSD) language originally tailored for the component-based field. It tries to stay as close as possible to the original Java syntax and concepts and introduces two new concepts: aspect beans and connectors.
Janino
Janino is a compiler that reads a JavaTM expression, block, class body, source file or a set of source files, and generates JavaTM bytecode that is loaded and executed directly.
ObjectTeams
ObjectTeams is a light extension to Java that provides support for advanced modularization. Role based programming provides the means to separate concerns, while features of aspect orientation provide a powerful adaptation/extension facility. An OpenSource, Eclipse-based IDE (currently based on Eclipse 3.2) supports designing, editing, refactoring, compiling, executing and debugging. Object Teams programs run on a standard Java VM.
Polyglot
Polyglot is a highly extensible compiler front end for the Java programming language. It is implemented as a Java class framework using design patterns to promote extensibility. Using Polyglot, language extensions can be implemented without duplicating code from the framework itself. Polyglot has been used to implement domain-specific languages, to explore language design ideas, to simplify Java for pedagogical purposes, and for various code transformations such as optimization and fault injection.
J&
J& (pronounced “jet”) is an extension of Java that increases code extensibility and reuse using nested inheritance. Nested inheritance supports inheritance of packages and classes while allowing classes nested within to be overridden.
Saffron
Saffron is an extension to Java to incorporate SQL-like relational expressions. It features a pre-processor, a query optimizer, and a runtime library.
Vorpal
The Vorpal language proposes a natural evolution of the basic Object-Oriented paradigm revisiting the duality data/knowledges with a new approach based on both Class-Oriented and Pattern-Oriented approaches in the same language.
language M
While adopting Java syntax, and a lot of its infrastructure, the language M fundamentally supports distributed, secure, persistent, capability-based computing, as necessary to support the notion of a world-wide collection of distributed virtual worlds
Whiteoak
The Whiteoak programming language is a Java 6 extension that supports: structural subtyping (structural conformance), virtual fields and constructors, mixin-like/trait-like composition of objects and more.
InstantJ
InstantJ is a library you can use to compile and execute Java code or evaluate expressions written in Java. This is done on the fly – there is no pre-compiling step necessary. This is ideal in cases where expressions are either assembled programmatically at runtime, are read from descriptors or received from user-input.