Jini is a set of APIs and network protocols that can help you build and deploy distributed systems that are organized as federations of services. A service can be anything that sits on the network and is ready to perform a useful function. Hardware devices, software, communications channels -- even human users themselves -- can be services. A Jini-enabled disk drive, for example, could offer a "storage" service. A Jini-enabled printer could offer a "printing" service. A federation of services, then, is a set of services, currently available on the network, that a client (meaning a program, service, or user) can bring together to help it accomplish some goal.To perform a task, a client enlists the help of services. For example, a client program might upload pictures from the image storage service in a digital camera, download the pictures to a persistent storage service offered by a disk drive, and send a page of thumbnail-sized versions of the images to the printing service of a color printer. In this example, the client program builds a distributed system consisting of itself, the image storage service, the persistent storage service, and the color-printing service. The client and services of this distributed system work together to perform the task: to offload and store images from a digital camera and print out a page of thumbnails.
Benefits of Jini technology:
1) Protocol Independence: Services can be discovered and implemented by using existing communication protocols. Default protocol used is RMI.
2) Location Independence: Network components need not be configured with explicit knowledge of location of the service to use the lookup services.
3) Services can be implemented with the needed dynamic modification without impact to clients.
4) Additional instances of services can be made use to enhance the load balancing and other performances dynamically.
5) Jini’s services are managed and monitored using JMX or SNMP.