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Jini , now called Apache River as a project of the Apache Software Foundation , is a framework for programming distributed applications that place special demands on the scalability and complexity of the cooperation between the various components and cannot be served by existing technologies. Jini offers a flexible infrastructure over which services can be provided in a network. Jini was developed by Sun Microsystems based on the Java programming language .

The made-up word Jini was created while looking for a sonorous name that begins with the letter "J" for "Java". The name Jini was ultimately chosen because it sounds like the English word genie [ dʒiːniː ] for a jinn from A Thousand and One Nights . The meaning of an acronym was only speculated afterwards. The trademark of Jini is an oil lamp , the dwelling of the subservient spirit in the story Aladin and the magic lamp .

The Jini network technology is an open architecture which enables developers to program adaptable network-based services - implemented in hardware or software . Jini can be used to create scalable and flexible networks as required in a dynamic computer environment.


The eight fallacies of distributed applications

  • The network is always available
  • The latency is zero
  • The transfer rate is infinite
  • The network is safe
  • The structure of the network does not change
  • There is only one administrator
  • There are no transport costs
  • The network is homogeneous

These assumptions about the network hinder the effective speed and distribution of the software. The following properties of Jini network technology help to overcome the pitfalls mentioned.

  • Code mobility - the programming model of the Java programming language is transferred to the network. It is possible for data and programs to be transmitted over the network as Java objects.
  • Protocol- independent - enables high flexibility in the design of the programs.
  • Leasing - enables self-healing and automatic configuration of the network. B. the fault tolerance is increased.
  • Flexibility - the network adapts to changes in the computing environment.
  • Integration - a simple and fast cooperation of old, current and future network components is made possible
  • Licensing - Jini network technology is available free of charge.

Jini architecture

The Jini architecture specifies how clients and services can find each other in a network and work together to solve given tasks. The service providers enable clients to access the services through Java-based objects. Network communication can take place using various techniques such as RMI , CORBA or SOAP , since the client only sees the Java objects offered by the service. The actual network communication is hidden by the Java objects of the service.

When a service that supports Jini is started in a network, this service broadcasts a message via a Java object that implements the service API . The implementation of this Java object is optional for the service. A client finds the services by looking for objects that provide the desired programming interface . After the client has found the published object, the necessary program parts are loaded in order to be able to communicate with the service. The developer of the service has determined how the communication between client and service should take place.

The existing Java platform makes it possible to define the Jini network technology. Jini extends the Java platform by making the services available within the network. The Java platform defines what functions are available on a participating machine. Jini technology extends the concept of a platform from a single computer to the network of computers that use the Java platform. Jini services do not necessarily have to exist on all computers in the network, but are available on all computers through the network.

Jini and UPnP

Jini and UPnP are different approaches to enable cooperation between programs and devices in a network. However, both approaches each provide a different level of implementation. While Jini, for example, already requires an existing network for communication between the participants in the network, UPnP also offers functions to configure the network between different devices and thus make it possible in the first place.

See also

Web links


  1. Rob Guth: More than just another pretty name: Sun's Jini opens up a new world of distributed computer systems. SunWorld, August 1998 [22. November 2008]