JSON-RPC: JSON-RPC is a simple remote procedure call protocol similar to XML-RPC although it uses the lightweight JSON format instead of XML.
JSON-RPC-Java is a Java implementation of the JSON-RPC protocol.Below is list of some of its features
Dynamically call server-side Java methods from JavaScript DHTML web applications. No Page reloading.
Asynchronous communications.
Transparently maps Java objects to JavaScript objects.
Lightweight protocol similar to XML-RPC although much faster.
Leverages J2EE security model with session specific exporting of objects.
Supports Internet Explorer, Mozilla, Firefox, Safari, Opera, and Konqueror.