Grengine is an engine for running and embedding Groovy in a Java VM.

Key features compared to what standard Groovy classes provide:

• Same scripts are automatically only compiled once already in basic usage (Grengine vs. GroovyShell).
• Improved thread-safety and more when grabbing Maven dependencies (@Grab) while compiling a script.
• Powerful features for robust and performant containers, including the unique (afaik) feature of caching compiled bytecode so that reuse in different classloaders requires no re-compilation, which also allows for much stronger session separation.

See the user manual for an introduction to some Groovy basics and the documentation of Grengine's features from simple usage (new Grengine().run("println 'Hello!'")) to complex container scenarios, all with examples.

© 2014-now by Alain Stalder. Made in Switzerland.

Overview

• Use Grengine 4 on JDK 17 and later and Grengine 3 on JDK 8 and later. Current versions of both have identical API and features, plus work and are tested with Groovy 2.5 to 6 on their supported JDKs (8 to 25).
• More details in the release notes at the bottom of the user manual.
• Apache 2.0 License.
• GitHub • Maven • Javadoc

Used by:        

"Powered by Grengine" logo:

Other open source software by me…

Jexler (2013-…): Jexler is a Groovy library plus webapp for running Groovy scripts at defined times.

LaTeX Package cmgraded (2026-…): Classic LaTeX look and feel in different grades of blackness.

Delphi / astrolib for PalmOS (2000-2002): Delphi is a very easy to use astrology program for PalmOS handhelds; astrolib is a library for calculating planetary positions and time zones. In emulators Delphi still works today on Android and iOS devices.

trueColor / trueTools for HyperCard (1996-1997): trueColor is a HyperCard Stack with which you can easily add color to other HyperCard stacks; trueTools is a collection of useful HyperCard stacks. In an emulator like "Mini vMac" the stacks still work today.