Jini: A Java-Based Network Dial Tone?

February 3, 1999

Chris Lehner

Sun Microsystems formally introduced its new connectivity technology, called Jini, last week, hoping to mark the advent of "spontaneous networking." The company boasts that Jini is a revolutionary breakthrough in the way electronic devices communicate. Jini will facilitate a network community of varied devices, ranging from productivity products, to home entertainment electronics, to household appliances such as dishwashers. This expands considerably on the plug and play principle built into Microsoft Windows 98, where the operating system automatically detects and configures drivers for any devices connected to the PC. Jini, however, does not require a PC as an intermediary; the participating devices negotiate their own interaction. The connectivity is made possible by the open nature of Java, which is used to write the interface code, and a protocol called Java Remote Method Invocation (RMI).

The way Jini works is this: when a Jini-supported device is plugged into the network, it announces its presence and capabilities to the network device registry, or "Lookup Service." It also uploads its object code to "JavaSpace" on the Lookup Service. The newly connected device is similarly made aware of other attached devices, which are available to share resources, such as applications and storage space. Distributed computing, or sharing of processing power, is also possible. This procedure is called "Discovery and Join."

To use a network resource, a Java object is downloaded from JavaSpace to the requesting device's Java Virtual Machine using the RMI protocol. The Lookup Service simply serves as a switchboard to establish the connection; once the connection is made, the devices interact directly. This ensures reliability and compatibility. There is no need for a traditional set of device drivers, nor is there a need to configure settings - Jini will self-configure and self-diagnose problems.

Sun first announced its Jini project in July of 1998. Since then, 35 companies have signed on to license Jini, including Sony, HP, Philips, and disk drive manufacturers Seagate and Quantum. Tech heavyweights such as Cisco, IBM, Novell, and 3COM are also involved. This level of industry support bodes well for the success of Jini. Another plus is the availability and low cost of microprocessors. Still, it is an ambitious initiative - all devices will need to be designed to support Jini. In addition, Sun faces competition from Microsoft, which is working on a similar technology, code named the Millennium

Project. Even with Microsoft's muscle, Sun enjoys the advantage of being first to market. Sun is encouraging development on the Jini platform by making the source code available for enhancement in a program called Community Source License. There is no charge to use Jini for research or internal deployment. Commercial use, however, will require payment of a licensing fee. Jini-supported equipment is expected to begin shipping in late 1999, the first devices being home office products.