FScript is an extremely simple scripting language. Its intended use is as an embedded language in other Java programs. It is very simple to embed - it can be a matter of sub-classing one class and adding your own functionality. However is not a complete programming language, i.e no libraries (for IO etc.) are provided. These are expected to be provided by the hosting application.
For a complete language I suggest you look at:
jython
- an implementation of
the excellent Python language in Java.
Rhino
- an implementation
of JavaScript in Java.
Both of these are also fully embeddable, and have sane licenses.
FScript however is around 50k as a jar file, and is only a few thousand lines of source. So if the functionality you are looking for is more than a simple configuration file parser, but less than a full blown programming language FScript could be for you.
As of version 1.1 FScript has the ability to access Java objects directly. That is it is possible to instance a Java object and access it's methods and fields from within a FScript script. This gives FScript a lot more power than it previously had. This feature is also modular and can be removed if not needed
A quick rundown of FScript's features:
The only requirement is a Java2 runtime environment. An initial version of FScript also exists for J2ME. For details so the FScript web site