Console Scripts

Straight from the horse's mouth at Oracle, this section offers information and examples like a beginning tutorial for coding Javascript console windows along with examples.

More information about them, from the website:

The Java platform provides rich resources for both desktop and web application development. However, using those resources from outside the platform has been impractical unless you resort to proprietary software solutions. No industry standard has defined or clarified how developers can use Java class files from other programming languages. Scripting languages haven't had a standard, industry-supported way to integrate with Java technologies.

Where better to start than with the actual creator (Sun, which was gobbled up by Oracle).

Visit Scripting for the Java Platform