The Kawa Scheme System is a full Scheme implementation, completely written in Java. Scheme functions and files are automatically compiled into Java byte-codes. Kawa does some optimizations, and the compiled code runs at a reasonable speed. It provides the usual read-eval-print loop, as well as batch modes. The Kawa compilation framework is also useful for implementing other languages on top of JVM. There is active development of XQuery (the XML query language), and less active development of Emacs Lisp, Common Lisp, and EcmaScript.
ecasound.el is an interface to ecasound from within Emacs. It allows you to use an inferior ecasound process in an comint-derived mode. It features context-sensitive completion and wizards for adding chainoperators and the like. It allows you to write ECI-based applications in Elisp.