ANTLR (ANother Tool for Language Recognition) is a language tool that provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing C++, Java, or Sather actions. It is similar to the popular compiler generator YACC, however ANTLR is much more powerful and easy to use. ANTLR-produced parsers are not only highly efficient, but are both human-readable and human-debuggable (especially with the interactive ParseView debugging tool). ANTLR can generate parsers, lexers, and tree-parsers in either C++, Java, or Sather. ANTLR is currently written in Java.
The Abacus Formula Compiler (AFC) compiles computations defined in spreadsheet files directly to Java byte code. Users can thus customize an application using Excel or OpenOffice Calc. AFC compiles against your own Java interfaces to obtain input values and compute output values (it essentially generates strategy implementations for you), and supports internal computations with either double or BigDecimal (for financial applications).
Absimpa is a Java class library that provides a recursive decent parser. It is an experiment in abstraction and Java generics. It tries to include only the essentials of what makes out a parser and to leave out, or rather leave free for specification, what is not relevant for the parsing process.
Aseba is an event-based architecture for distributed control of mobile robots. It targets integrated multi-processor robots or groups of single-processor units, real or simulated. The core of aseba is a lightweight virtual machine tiny enough to run even on microcontrollers. Robots are programmed in a user-friendly scripting language using a cozy integrated development environment.