Kawa

http://www.gnu.org/software/kawa/
Kawa is:
A framework written in Java for implementing high-level and dynamic languages, compiling them into Java bytecodes.
An implementation of Scheme, which is in the Lisp family of programming languages. Kawa is a featureful dialect in its own right, and additionally provides very useful integration with Java. It can be used as a "scripting language", but includes a compiler and all the benefits of a "real" programming language, including optional static typing.
Implementations of other programming languages, including XQuery (Qexo) and Emacs Lisp (JEmacs).

For lots of Scheme resources, see www.schemers.org, including an online copy of the R6RS standard. A nice quick introduction to Scheme can be found in Greg Badros's lecture notes. A more in-depth tutorial which also discusses Scheme implementation is Paul Wilson's "An Introduction to Scheme and its Implementation".
For a technical overview of Kawa, see these http://www.gnu.org/software/kawa/internals/index.html. Javadoc generated documentation of the Kawa classes is also available. The packages gnu.bytecode, gnu.math, gnu.lists, gnu.xml, gnu.expr, gnu.mapping, and gnu.text, are used by Kawa, and distributed with it, but may be independently useful.