Json-lib is a java library for transforming beans, maps, collections, java arrays and XML to JSON and back again to beans and DynaBeans. It is based on the work by Douglas Crockford in http://www.json.org/java.
JsTester allows validation of javaScript code inside java. It provides a group of assert methods like JUnit's Assert, it also supports the validations in http://javascript.crockford.com, and the ability to use your own validations.