Overview

This chapter gives an overview of Jini, thereby providing an example of a well-known distributed-object based system. Jini is similar in concept to industry-pervasive systems such as CORBA [126] and DCOM [127]. It is distinguished by being based on Java, and deriving many features purely from this Java basis (e.g., the use of RMI and Java serialization). There are other Java frameworks from Sun which would appear to overlap Jini, such as Enterprise Java Beans (EJBs) [16]. However, whereas EJBs make it easier to build business logic servers, Jini could be used to distribute these services in a network plug-and-play manner.

In this chapter, a background is given into the development of Jini and into the network plug-and-play manner in which Jini accesses distributed objects. Specifically, Java RMI is discussed, which forms the transportation backbone, along with Java serialization. The discovery of Jini services is described and the notion of a Jini proxy is introduced.

Jini implements three protocols that allow a service provider to register its service, a client to search for the service and both a client and service provider to discover the Jini look up server. The Jini look up server is central to the control of the Jini environment as it coordinates the discovery and registration of Jini objects. Jini runs a brokered architecture however, in that the discovery is centralized through the look up service but the communication thereafter between the client and the service is direct.

Finally, Jini advanced issues, such...