Not specifically recommending this for adoption...more of an interesting observation...as I'm currently doing some research for a client engagement...
Invoke dynamic languages dynamically, Part 1: Introducing the Java scripting API
Invoke dynamic languages dynamically, Part 2: Find, execute, and change scripts at run time
Creating a simple rules engine using the Java scripting API
jsonrules: A Rule Engine in the Web browser (2009 – alpha version was published, not much activity since)