Lookup

The Jini Lookup functions as a network bulletin board and clearinghouse for all services on the network. Unlike DNS which only contains IP addresses and their corresponding host names, Lookup stores pointers to all the services available on the network and also the actual code and/or pointers to the code for these services.

As an example of Lookup, let's examine how a printer would be added to a network using Jini technology. When the printer was first plugged into the network, it would load a printer driver, or an interface to the driver, into Lookup. When a client wants to use the printer, the driver and driver interface would get downloaded from the Lookup onto the client. In this way, clients do not need to be loaded in advance. Of course what makes all this work in a simplified fashion is the power of Java's write-once-run-anywhere model. The Java printer driver is guaranteed to work on any client with a Java Virtual Machine. Without Java technology, trying to store all the possible different printer drivers on the Lookup would be next to impossible.