Jini is a network centric coordination based middle ware architecture for distributed systems. It was developed by Sun Microsystems. Architecture of a Jini is a simple network centric one with many Jini devices connected to a network. These Jini devices are used for providing services in the network. A Jini device can be a computer, mobile phone, printer, scanner, TV, etc. When a Jini device has to be hooked in the network, the discovery protocol is used for locating a lookup service. After the lookup service is located it responds to the Jini device in (JVM) Java Virtual Machine language. This code is run by the Jini device for registration. After the registration, the Jini device becomes a part of the network. This registration is for a specified time. Later, if the Jini devices requires it can again register to the network.
JavaSpace: Jini devices in a network communicate by using JavaSpace. JavaSpace is a process of implementing the concept of tuple space in Java. There are 4 methods which are used in JavaSpace:
1) read method: It is used for returning a copy of an entry which matches with a template.
2) write method: It is used for adding a new entry in JavaSpace.
3) notify method: It is used for notifying the caller when a matching entry is written.
4) take method: It is used for removing an entry which matches to a template and then it is returned to caller.