Java: embedded in the core network
Abstract: Java: embedded in the core network
Although some on the market today embedded solution does not require network access, but the era of independent equipment is gradually dying out. With Internet telephony, Internet television, smart cards, and personal digital assistants, and other innovative devices embedded in a large number, and the growing need for network customer identification system, and those who allow them to insert and access various services standard, that is, at any time, any place and Based on any platform, and the realization of any person connected.
And desktop systems, consumer devices use a variety of user interface technology, storage space and a relatively small screen specifications, and configure embedded processor, energy consumption, user response time and physical space, and other areas were severely restricted. Consumer devices must be independent and not run on a system management functions environment. In view of this, and consumer equipment failure can not. Java platform has many characteristics of this type of equipment makes it an ideal choice. Dynamic Link and loading characteristics, allowing remote software updates and patches, as Java byte code than the small machine code, the code need only minimal storage space; Java programming language is object-oriented language that allows modular code and multi-purpose, all the application code does not require a permanent presence in the equipment to use the Java platform, code can be downloaded only when necessary to equipment; Java application environment safe and reliable characteristics (including the elimination of the guide, direct memory access, border checkpoints to prevent illegal dumping and stack overflow), will ensure that no unauthorized objects from consumer devices in the local memory read and write data or code.
Currently, Sun offers a complete embedded Java solutions, including PersonalJava, EmbeddedJava and Java Card Application Programming Interface (API), they were applied to different applications environment.
PersonalJava
PersonalJava platform is designed for the individual consumer devices and networking applications designed for home, office and mobile users. Configuration of a variety of display technologies such as television equipment, and usually not the keyboard or mouse input and the implementation of navigation products can be used PersonalJava platforms.
PersonalJava is a Java application environment (JAE), which by the Java Virtual Machine and Java application programming interface subset of the components, including both core and optional application programming interface and libraries. In addition, PersonalJava application programming interface also includes consumer applications in the environment of limited resources demand for properties. PersonalJava application programming interface and application programming interface EmbeddedJava share a common core group application programming interface, we can run small programs, and support relatively sophisticated visual displays, but also networking. PersonalJava application environment applicable to the equipment, including mobile handheld devices, set-top devices, game console and the smart phone.
PersonalJava platform includes the following components:
Java Virtual Machine: bytecode interpreter, byte code inspection, loading category, as well as Unicode text support, 32-bit and 64-bit integer, garbage collection, multi-dimensional arrays, floating-point operations, threads, exception handling features;
Demand Java categories: input / output, language support, application;
Internationalization (I18N) support: product use software buns in a comprehensive set so that only developers choose to support only the language, thereby reducing space and memory usage;
Java Beans, Java applets, the network;
Support code signing (digital signature);
Consumer products to look and feel as the goal and made corresponding adjustments JavaAWT version. It can provide graphics and window features, support for low-resolution display and optional input devices (through a mouse and keyboard equipment without incident expansion model to be achieved).
Each of Java application environment (JAE) by the core application programming interface and extend the standard (optional) application programming interface. PersonalJava the hierarchical structure from low - to high-order: Java Virtual Machine, Math, input / output, language support, functional class library, international, Java Beans, network functions (NetWorking), Java Applets and AWT.
PersonalJava environment custom application development tools, including JavaCheck pre-processor, it can test the code and PersonalJava application environment consistency. Other tools that will allow developers configure, compile and the creation of images, set up in the ROM executable code, implantation optional HTML, image, voice and data files.
EmbeddedJava
EmbeddedJava application environment for embedded devices designed. Such equipment configuration dedicated and very limited storage space, and does not require general Web browsing. EmbeddedJava application environment to provide a set of tools to allow developers to meet the needs of specific applications, configure and compile the necessary fields and includes only method of the environment, can be read-only memory in the system integrity of the environment for such formation and installation of executable image . A developer can use the EmbeddedJava application environment to create a variety of products, including low-end mobile phones, pagers, process controller, test equipment, office printers and peripherals as well as network routers and switches.
EmbeddedJava applications to run in real-time operating environment, to suit the small storage space in the visual display equipment and diversification has been optimized processing. EmbeddedJava application environment allows equipment manufacturers in its software products, use of the Java programming language portability and flexibility.
Configurability
When the storage space is severely limited the embedded device design software, in accordance with the application requirements configuration environment is a crucial factor. If the device (such as pagers) does not require file system, not on the configuration file system support functions. EmbeddedJava application programming interface provides a number of tools, the ability to achieve such a configuration. If JavaFilter (TM) technology is generated in order to assess applications and application needs of the fields and methods table JavaCodeCompact will use the table, choose from a Java application environment specified fields and methods; JavaDataCompact can read static data, such as documents or images HTML documents; developers to use these tools, can be read-only memory (ROM) to install executable code, configuration, and even the compiler for images, it is estimated that the resources needed.
Performance
In the network routers and switches that run on one type of equipment embedded applications, the design goal is to the final product, and maintain the hardware provided by the real-time support. In other words, these products require high performance. Therefore, the application programming interface EmbeddedJava the purpose is to use real-time operating system. Considered in the design of performance and transplantation factors.
Upward compatible applications
As long as the corresponding equipment support capabilities, and applications can EmbeddedJava PersonalJava (TM) and upward compatible with the Java platform, and run on these platforms.
EmbeddedJava compatibility
At present, the Sun is planning to develop a compatible programs is for the purpose of EmbeddedJava platform for achieving consistency. Java platform certification process and the current process of the same.
Java Card
Java Card specifications for the Java technology in the smart card and the storage space is very limited and other equipment running created. It offers platform independence, storage and the ability to update multiple applications, as well as with existing smart card standards compatibility, a growing number of smart card applications, excellent flexibility.
Java Card application programming interface allows for the preparation of a smart card platform applications, and Java card technology in any other such platforms to run on. Java Card Application Environment (JCAE), the original equipment manufacturer basis, the smart card manufacturers to licensing, these manufacturers on behalf of the global smart card manufacturing capacity of more than 90%.
Java smart card technology has the following unique advantages:
Platform independence. Java card with the Java API specification cards on the procedure will be run on JCAE developed by the use of the smart card, allowing developers to use the same Java Card small program from different vendors, running on smart cards.
Multi-application functions. Can run multiple applications on a single smart card. Java programming language to the inherent design of small downloadable code elements as the center, can be safe and reliable and convenient in a single smart card to run multiple applications.
Dynamic adaptability. Smart card issuers, the application will install smart card issuers to provide a dynamic approach to customer needs change. If the customer decided to change the smart card associated with the common procedure, the smart card issuer to meet its requirements, without issuing new cards.
Flexibility. Java Card technology uses object-oriented methods, procedures for the preparation of smart cards to provide flexibility.
And the existing smart card standards compatibility. Java Card application programming interface not only with the formal such as ISO7816 international standards compatibility, but also with Europay / MasterCard / Visa (EMV) for such a class of the industry standard compatible.
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Tags: network, the core java technology