Jini technology Overview

Question 1: What is jinitm technology?
Jini technology is a new technological breakthrough based on Java technology. It enables various devices to easily connect to any unprepared Network (impromptu network, in this way, the access and transmission of new network services become as simple as the Access Phone. The Jini technology built on the basic structure of Java software enables all types of digital devices, without a large amount of planning, installation, or human intervention, run together in a community. Each device provides services that other devices in the community may need. These devices also provide their own user interfaces or program interfaces, which ensures reliability and compatibility.

Question 2: What is the unprepared community (impromptu community )?
The unprepared community can describe the situation when two or more devices using the Jini technology share their services together. Because devices do not need to have a prior understanding of each other to connect to the community, it can be said that the Community is not prepared. Jini technology allows devices to dynamically establish communications to share and exchange services in the network. The unprepared community is a dynamic environment that eliminates the need for device configuration or driver installation.

For example, assume there is a camera connected to the network. The camera immediately connects to the network without the need to install a driver, insert a CD-ROM or floppy disk, and type commands from the keyboard. The camera identifies itself and provides services. If the camera can speak, it may say, "I'm a camera. Who wants to take a photo? "You may have a laptop that uses the Jini technology to join the network. In this case, you may access the camera and take a photo of it, and send the photo to your own disk drive, or send it to another device for printing.

Question 3: What are the benefits of Jini technology?

All Jini technologies are designed to simplify online interaction. The Java platform has simplified the startup, while the Jini has further improved it. Simplified means improved productivity, reduced costs, and ease of use. Jini technology makes it as simple as using a phone. It allows ISVs, ihvs, and component manufacturers to expand to new markets and provide network-based improved products and services. Jini software also allows traditional service providers to dynamically add and manage network services.

Question 4: Where are Jini Technologies commonly used?

Almost all devices that need to process digital information input and output may be connected to communities that use Jini technology, not only traditional computer hardware and software, but also applications of consumer goods, such as personal digital assistant (PDA), digital camera, video recorder, TV, DVD player, cell phone and CD player. Traditional component and peripheral manufacturers have shown great interest in this, and they all want to turn themselves into value-added network service providers. In addition, enterprise service providers are also very interested in this, and they want to simplify and expand their network capabilities.

Question 5: What development trend does Jini technology cater?

As the price of processors and other technical devices declines, the definition and use of traditional computers are expanding. The technologies used have evolved from the original single-user PCs and millions of dollars of large computers to today's network-based computing applications. Investment in broadband networks that can connect the world is still ongoing. Network devices are not limited to traditional computers. On the contrary, from digital cameras to cell phones to household appliances, they all use some type of microprocessor and have a certain degree of network intelligence. However, today's network is still complex for general users and is not easy to manage and use. They are looking for simpler and more reliable network solutions. Sharing and computing information, data, and services through networks like utility tools will become increasingly common. Distributed computing technology will be used to control various functions of the network. In many fields, due to the widespread use of Java technology, it will provide a "write once, run anywhere" software platform. This development trend of the network-available everywhere, simple, using Java and distributed computing technology-laid the foundation for the emergence of Jini technology.

Question 6: How does the industry respond To Jini technology?

The response was very enthusiastic. The market demand for technologies that can simplify the network is very large. Sun provides free source code for Jini Technology for research and non-profit (within the Organization) purposes. Therefore, a large number of organizations have begun to investigate Jini technology. At the same time, a large number of companies engaged in electronic consumer goods, computer external equipment, enterprise-level computing, computer systems, network service supply and software have also purchased Jini technology licenses, jini technology is also used in its commercial digital products and services.

Question 7: What are the main designers of Jini technology?

Under the leadership of Bill Joy and Jim Waldo, some elites in the distributed computing field participated in the Jini Technology Development Project. They include Java remote method calls (Java RMI) and the designers of Ann wollrath and javaspaces. At the same time, Ken Arnold, author of Java programming language, and the owner and Lookup (Lookup /discovery) bob scheifler.

Question 8: Where can I find more information about Jini technology?

For more information about Jini technology, visit the following url: http://www.sun.com/jini

Jini technical details

Question 9: How does Jini technology work?

Based on relevant protocols and a set of Java technical interfaces, Jini technology enables devices and applications to enter the unprepared community of online virtual machines. Devices using Jini technology use a process called discovery to find devices using the same Jini technology. Then these devices can send objects to the Lookup service of Jini technology-these objects represent the services provided by the device and their defined features and attributes. When a device needs to use a service in the community, it can download the required objects from the Jini search service, including any code, such as applications, device drivers, or user interfaces.

Question 10: What happens when a new device is connected to the network?

To provide services to the local community, the device must use Jini technology to register the services it provides. This can be done in two steps. First, the device polls the local network to confirm the location of the Jini Lookup service. Then, it registers itself on the Lookup service. These two steps are called the discovery and join processes. For each service provided by the device, the process uploads a Java object to the search service as the interface of the service.

Question 11: on which devices can the Jini software run?

Jini software is Java software code. It can run on any digital device, such as cell phones, digital cameras, personal digital assistants (PDAs), and even smart magnetic cards.

Question 12: to use Jini technology, do all devices on the Internet use the Java platform.

No. These devices allow other components on the Internet to represent them to execute Jini software that requires Java technology. By entrusting some specific Java functions required by the Jini software to a third party, a device does not have to have its own virtual machine, and almost no additional code is required, to become a component of the Jini Technology Network. All functions required to become an integral part of the network community can be implemented by another system that is in partnership with the device in the network.

Question 13: How can I know that I have a Java virtual machine on the Internet?

Whether you know or not, your machine may already be using one or more java virtual machines. They are nested in most Web browsers and various devices. If a response is returned to a query of a discovery, it indicates that a Java Virtual Machine is available on the network.

Question 14: How does one application use Jini?

To use services in the community, an application must first use the Discovery Protocol to locate a Jini search service, then, it can use the search service to locate the device that can provide the required service type. The application can download a Java object from the search service that can be used to interact with the selected device. This object is used to process any device-related details; the machine running the application does not need to have the driver of the device.

Question 15: What if a device is disconnected?

Jini uses a technology called "leasing" to detect when a service is unavailable. When a device is registered with the search service, it receives a "lease ". This lease must be updated on a regular basis. If the device is not updated, the device is deleted from the service list. Deleting a device does not affect the status or service provided by other community members.

Question 16: Does Jini technology apply to my current network?

Because Jini technology is based on the Java platform, it can run on any network with at least one Java Virtual Machine (JVM), including a network using a traditional operating environment, for example, a network that uses Novell Netware or Microsoft Windows.

Question 17: Do I need to replace the existing software or hardware with the Jini technology?

No. By adding some Jini software, existing digital devices can be upgraded to use Jini technology. For example, once your PC has Jini software, it can use the services of other devices, and it can also be provided as a service to other devices. Even devices connected to your PC, such as disks or printers, can be provided as services to other devices after appropriate Jini software is added.

Even if the PC is upgraded to use Jini technology, the existing software used on the PC does not need to be changed. By changing software and providing services on the network, you need to upgrade the software.

Jini Technology Development

Question 18: Can I add the Jini technology to my current software? What should I do?

Yes. The first step is to provide a Java software package for your code so that the code can run in a Java Virtual Machine (JVM. You can find a good text description of this process, because thousands of developers currently want to implement this process. The second step is to add the programs that can tell you to declare their own code to the search service. We will provide some sample code and upgrade tools to help you complete this step.

Question 19: What is the Jini technology community?

The Jini technical community is composed of any development organization or individual interested in creating applications or services. Members of this community must execute the basic sun community resource license (Sun community source licence (SCSL) Protocol) for access to Jini technical source code. They share certain powers and responsibilities to protect the open and scalable nature of Jini technology. These members can participate in user groups, development forums and consultancy seminars, and may also receive development and technical support from Sun Microsystems and other community members.

Question 20: What kind of plans does Sun have to support various organizations to use Jini Technology for Development?

To encourage innovation in the Jini technology community, Sun provides comprehensive technical information, support services, and market support for commercial products using Jini technology. Sun's plan helps developers explore new uses of Jini technology from free web sites with deep technical information and shared resource libraries to professional technical support and super cooperative marketing opportunities, develop innovative products and services and create user requirements for using Jini software.

Question 21: Are there any Jini development tools available?

Because Jini technology is based on the Java platform, any existing development tools that can be used in Java software development can be used in Jini software development. In addition, Utility Classes and implementations are being developed and available for free. This will reduce the difficulty of Jini-based services and client development.

Question 22: Is there a visual development tool for creating a Jini technical component or service?

At this early stage, there is no commercial visual toolkit for Jini technology. However, we do expect community members to be able to submit such tools, and we encourage business companies to develop toolkit similar to other technologies for Jini technology.

Question 23: Can Jini technology be obtained now? How can I get it?

Yes. Source code and specifications of Jini technology core platform (kernel platform) can be downloaded from the Internet. URL: http://www.sun.com/jini /. Although it can be downloaded for free, you must click the mouse to accept Sun's community resource License Agreement (Sun community source licence (SCSL )).

Question 24: How does the community resource License Agreement work?

Sun's community resource license (SCSL) protocol is a license model designed to publish resource code in the developer community. This model is based on Sun Microsystems's recently released Community source licensing principles, designed by Richard Gabriel and Bill Joy.

To promote and improve Jini technology, Sun basically shared the source code right with other members in the developer community according to the SCSL protocol. Sun is also committed to establishing a responsibility to ensure compatibility, and proposes a business model-creating patent improvement projects by advocating agreement recipients to reward innovation and invention.

For details about the further operation of the Community Resource License Agreement, see the Licensing section of our website at http://www.sun.com/jini/licensing /.

Question 25: What is the price system of Jini technology?

For those protocol recipients who wish to evaluate, improve, and improve the source code of the Jini technology and use it internally, as long as they comply with the sun community resource license (SCSL) protocol, jini source code is free of charge. Once you or your company decides to use Jini technology products commercially, you must agree to the commercial terms of use in SCSL (Annex E, and sign the Jini compatibility logo (Jini compatibility logo) license agreement. The license includes the annual price or unit price of the logo ).

Question 26: Can I update the source code?

All protocol recipients of Jini can access our Jini technical site. Here, we have arranged a region for the Protocol receiver (including Sun itself, enable them to send program debugging, updates, tools used, examples, and other technical support issues related to the Jini technology to other members of the community. We look forward to receiving new information every day. Sun will make necessary changes to the core code whenever and wherever appropriate. All the situations will be notified online.

Question 27: How can I send the code back to the Jini technical community?

We have detailed steps in this regard on our website. The URL is: http://developer.java.sun.com/developer/products/jini/index.html.

Jini and Java Technologies

Question 28: Which version of Java software is required by using Jini technology?

Jini technology relies on some features of the recently released Java 2 software. The communication between devices is completed using Java remote method call (RMI. Security is provided by extending the Java software security model. Object serialization is used to pass device interfaces to the search service and any applications that want to use the device.

Question 29: Why does Sun use Java remote method call (Java RMI) in Jini technology )?

Java RMI is the basic underlying structure of Jini technology, because only RMI can implement the architecture of Jini software. Java RMI allows objects (including their actions) to be passed according to their actual Java software type. This allows a sub-type transfer of objects of the expected basic type, and allows the Code implemented by the same service interface in different ways to be passed to the client of the service as instructed.

Without Java RMI, Jini technology cannot be implemented.

Question 30: Can Jini technology run with Microsoft virtual machines?

No. Jini technology relies on the Java 2 environment, including enhanced RMI, security, and collection classes. Currently, Microsoft virtual machines are not implemented in Java 2.

Question 31: Why is the Jini technology isolated from the Java platform?

Jini technology is an extension of the Java platform, which brings the advantages of Java technology to the network. However, it is completely different from the Java platform-for example, it is not suitable for an independent system (stand-alone system ). Furthermore, given the network-centric features of Jini technology, it is not suitable for general Java platforms.

Question 32: How does Jini technology work in coordination with other Java functions?

The underlying structure of the Jini software is written in the Java programming language and can work together with all the core Java technologies.

Question 33: Does Jini technology adapt to Enterprise JavaBean components?

Enterprise JavaBeans (EJB) components can be used as the development and deployment models for server components. By adding the underlying structure of Jini software to these components, EJB can easily become a service of Jini technology.

Question 34: What is paces?

Javaspaces technology is a service provided for the simple communication and storage of Java software groups.

Question 35: Do I need a complete transaction management program to use Jini technology?

Using Jini technology does not require any transaction management program. The service can use the free Jini two-phase commit Transaction Management Program, or any other transaction management program suitable for them, or does not use the transaction management program at all.

Question 36: Can I use Jini Technology in ejava and pjava?

Both technologies will be improved based on the Java 2 environment to better support Jini software. The development schedule will be made public soon.

Jini technology and operating system

Question 37: Is Jini a network operating system?

No. The Jini software runs on the Java platform and is used to create a virtual machine consortium structure. Each virtual machine runs on a system, and the operating system runs on the network. A network operating system is an operating system that includes software that communicates with other computers over the network. UNIX and Novell Netware are examples of network operating systems.

Question 38: Won't windwos ce do the same thing?

No. Windows CE is an operating system that can be installed on devices that are independent from traditional computers. Jini is not an operating system. It is a programming model that allows developers to create and manage their own operating environments and connect to a common network. The device can manage itself and operate according to a set of network-based rules. The operating system used by the device is determined based on the user's consideration.

Question 39: What is the difference between Jini and Microsoft's plug-and-play technology?

Microsoft's plug-and-play feature is not available in all aspects. According to the reports on its underlying structure, we believe that this feature cannot be compared with the Jini technology. The plug-and-play feature is defined by a closed group bound to the Microsoft operating system and led by Microsoft. The Jini technology is independent of the operating system and controlled by the Jini software user community. This user community has the right to access, expand, and change the Jini technology source code for free. Plug-and-play is about how to connect to a device. It requires that the device driver code be provided to the customer or manually installed by the user. The Jini technology is about how to connect services. Such services can be either devices or software, jini technology's inherent code flexibility allows devices to pass their driver code to customers without user intervention.

Jini and other search technologies

Question 40: What will happen if the network search technology using Jini is compared with other directory services such as LDAP and JNDI (Java Naming and Directory Interface (TM?

The search service in Jini is a lightweight but powerful service library.

It uses the type system of the Java platform as the namespace. This structure is unique-this means that it does not store fixed name-value pairs (name-value pairs ), instead, it stores objects and object graphs that reflect the actual behavior of objects. This has two obvious advantages in a distributed system. First, you can search for an object or service based on your expected behavior, instead of simply using their names. Second, once you find an object in the directory, even if you have never "seen" it before, you can immediately know how to use it.

For example, you may want to find a storage service. You can directly send requests for certain behaviors, such as mobile, fixed, local, and remote requests. According to your request, you can receive several options, including writable CD, zip driver, and many other media types installed on your network. Once you select a service you want to use, the interfaces and drivers of the service are automatically included in your selection, so you don't have to worry about whether they have been installed.

Jini's search technology is designed as a service for these requests. LDAP and JNDI support other services that are equally important to you. Jini technology does not have to replace your existing systems. enterprise-level directory services can be provided as services in Jini Technical Services, which allows customers to easily find the enterprise-level information they need.

Question 41: What is the relationship between SLP And Jini?

The Jini technology and the service positioning protocol are both dynamic search service mechanisms on the network. However, unlike SLP, Jini technology is based on the Java platform and provides code flexibility. Code flexibility means you can move code on the network and behavior (proxy) related to it ). You can store any Java object or object graph in the Jini Search Service, including the driver, proxies, smart proxies, and GUI. Applications can use the Lookup service to extract and execute them.

Question 42: I have heard of an industry new invention called salutation. Is it similar to Jini technology?

Salutation provides a search service similar to the service library called Information Management Service (IMS), which is similar to the search service of Jini technology. However, IMS only supports searching by name-value pairs, but does not support searching by object type like Jini technology. Salutation allows mutual searches between services, but once found, it directly uses RPC. Because Jini is based on Java technology, it supports code portability. This allows you to use the agent to move behavior on the network.

Question 43: is havi a new invention of the home network. Does Jini technology apply to it?

Havi is a Home Network System for household electronic devices. Jini technology is applicable not only to the home network environment, but also to enterprises and the Internet. The havi organization has recently announced that it will use the Java programming language as its selected language, which makes it easier to integrate havi into a network using Jini software. We expect that Jini-based software bridges allow seamless sharing of havi devices and services.

Question 44: Is HP's jetsend protocol similar To Jini software?

HP jetsend is an information exchange protocol designed for fixed functionality and programmable devices. Jini technology provides an architecture for both software and hardware services and supports code flexibility for dynamic behavior. With Jini technology, services can be dynamically discovered and automatically registered, and drivers can be automatically installed. By providing a gateway between the jetsend device and the Jini technology, the jetsend device can run together with the Jini technology.

Jini technology and supplemental Network Technology

Question 45: Does Jini technology adapt to FireWire technology?

Firewire technology is mainly designed to simplify the connection between PCs and external devices. By providing a method to connect external devices to a large network and the Internet, Jini further improves FireWire and USB technologies. Jini technology also provides additional services, such as leasing, transaction processing, and structured pace technology. We expect to see Jini technologies built on those important technologies.

Question 46: Is Jini applicable to USB?

Universal Serial Bus (USB) is a network transmission layer designed to adopt the "plug-and-play" function in hardware. Although it solves some problems that can be solved by Jini technology, Jini technology makes USB develop further. Jini technology is a separate and unified transmission layer that can communicate directly with the network. services using Jini technology can be either hardware or software. Jini technology applies to USB, just as it applies to Ethernet and firewire.

Question 47: Is Jini applicable to home PHONELINE networking Alliance (hpna?

Hpna is an innovative solution that provides "Ethernet" capabilities for existing household phone wiring. Hpna mainly solves various existing household wiring problems (older single-to-untwisted pair wires, 3-type twisted pair wires and 5-type twisted pair wires) and how to manage bandwidth restrictions on various wiring topologies. This technology is not intended for the concept of "spontaneous network". The guidance and addition of devices in the spontaneous network is carried out together with other devices in the home or office. Hpna may be a potential sending mechanism of Jini Technology in the home. Here, the home network wiring does not exist, or the cost of installing such wiring is unacceptable.

Question 48: Is Jini suitable for Bluetooth?

Bluetooth is a network transmission Technical Specification designed for low-cost, short-range radio connections between PDAs, laptops, mobile phones and other portable devices. When two bluetooth devices are close to one another, they can automatically detect the other and establish a network connection. Then, they can use the Jini technology to find other devices that can provide the services they need. Jini technology applies to Bluetooth, just as it applies to other network transmission protocols.

Reprinted Source: http://blog.csdn.net/romans1981/archive/2005/03/15/319725.aspx