ScriptEngineFactory.getLanguageVersion() and ScriptEngineFactory.getEngineVersion() APIs return version information of the engine. But, for JavaScript engine these methods return '0' and "@IMPLEMENTATION_VERSION@' respectively. These should return '1.6' and '1.6 release 2' respectively.

jrunscript -q outputs:

Language ECMAScript 0 implemention "Mozilla Rhino" @IMPLEMENTATION.VERSION@

The output should look like:

Language ECMAScript 1.6 implemention "Mozilla Rhino" 1.6 release 2