FAQs

More concretely, Jini technology is defined by a set of specifications that describe how to build adaptive distributed systems that run on the Java platform. The specifications presume, fundamentally, that any aspect of a distributed system is subject to change without notice, and so they provide systems designers and developers with the mechanisms needed to recognize, acknowledge, and build their systems to accommodate change.

Jini technology specifications are straightforward and minimalistic. They describe the following:

• runtime service discovery mechanisms that enable clients to find and connect to individual services as needed in a dynamic operating environment
• a programming model that extends the Java programming model to acknowledge and accommodate network behaviors such as partial failure
• key services, such as shared memory and transactions management services, that enable important functionality to be delivered in a dynamic, distributed environment

Edge Networking
Distributed systems deployed beyond the data center are differentiated from their data center-focused counterparts in that they are subject to a wider range of failure modes, and they are not readily accessible to a systems administrator. These systems must be able to automatically recover from failure at the network edge, and must be easy to update and manage without manual administration as well. Jini technology has proven itself up to the task; it is being used today to enable the creation of self-healing edge-networking systems, and to allow new or updated services to be introduced into these systems without the need for an administrator to restart the system

Compute Grids
Jini technology is being used today as the underlying infrastructure supporting compute grid applications in financial services, defense, logistics planning, life sciences, image processing, scientific research, manufacturing, and other domains. Jini technology-based grids automatically accommodate the runtime addition, removal, or loss of compute resources, which means that these grids can scale dynamically to accommodate changing loads, and they keep running even though some large grid networks operate in a near constant state of partial failure.

Dynamic Systems Integration
Jini technology is today supporting many companies' needs to keep their systems up and running while dynamically integrating in house or third-party services whenever they are available. The technology is helping these users deal with service failures, updates, and implementation details that are beyond their control, often stemming from their need to integrate services from external sources. Also, by isolating clients from the need to implement any of the multiple proprietary communications protocols that many different service providers use, Jini technology is simplifying these users' approach to integrating services that use a variety of communication protocols.

Dynamic Clustering
Whether they are used to increase availability or scalability, clusters created with Jini technology are successfully accommodating the run time addition, loss, or removal of clustered services for many users today. These Jini technology-based clusters scale out readily with the simple addition of service instances to be clustered, and they scale down just as easily by removing unneeded service instances. The location, name, or provider or any service to be clustered can be changed without the need to bring these clusters down.

Workflow/Message Switching
Jini technology, and especially the JavaSpaces service, provides a simple way to share Java objects across a dynamic network. Telecommunications, financial services, and other applications are exploiting the technology's support for loosely coupled interactions and its ability to transfer data (and/or code) through the system.

Ad-hoc networking
Jini technology is today being used to enable the spontaneous bootstrapping of a network of services that come together in an ad-hoc fashion. Current deployments are using this capability to power solutions in a range of new ad-hoc networking markets, including home networking, telematics systems, and sensor networks, to name a few.

Dynamic Service Provisioning
The ability to flexibly provision networks to offer specific configurations of services that may be re-provisioned to accommodate changing needs over time is what underlies the move to utility computing today. Developers have leveraged Jini technology's support for dynamic service discovery and delivery, as well as its straightforward service substitution capabilities, to create such dynamic service provisioning infrastructures.

This contrasts sharply with other approaches to networking, in which networking contracts are defined in terms of how clients and services interact, rather than in terms of what functionality is needed/provided. Traditional network clients and services must be implemented against a pre-defined and shared understanding of service naming conventions, IP addresses, or over-the-wire communication protocols. Using these traditional network architectures, running clients may be unable to bind dynamically to services that provide needed functionality if the names, locations, or wire protocols used by those services vary from time to time or place to place.

Java Dynamic Networking places no such conditions on the networking contract between a client and service: as long as a service is capable of providing the functionality needed by a client, that service can be bound to the client at runtime. This leads to more flexible component interchangeability, and ultimately increases the adaptivity of systems that use Jini technology and Java Dynamic Networking.