Source of brew and j2's

Professionals expect most new information devices to be connected to the Internet in the next two to five years, which will lead to fundamental changes in the way users use these devices. Users can easily transmit webpage content, enterprise data, and personal data anytime, anywhere, and on any device they use. To meet the ever-expanding demands of these information devices, Sun has launched the j2-qualcomm and brew, two new online wireless application models.

Brew

Brew is short for Binary Runtime Environment for wireless. It is a common content that Qualcomm provides for wireless data application development and execution. Because fewer internal application development and integration tasks are required, OEMs can launch new devices more quickly. Users can select and download Wireless Software suitable for their personal preferences. In this way, users will promote the development of new wireless data applications and service markets.
The Brew runtime environment is a thin software interface layer located on a wireless device between the chip system software and applications, this allows end users to download programs wirelessly and run them on BREW enabled devices. Brew has high flash memory and RAM usage efficiency-it occupies less flash memory and dynamically allocates Ram to it when the application is running.

1. BREW application platform

The complete brew solution begins with an open and standard application execution platform where wireless devices reside.
(1) Thin-brew is not only a scaled-down version of a product developed for a PC or PDA, it is much smaller than other application platforms or mature operating systems. Qualcomm is a wireless company that understands the Needs of the wireless industry and designs the BREW Platform from the chip.

(2) fast-The BREW Platform is located on top of the chip system software, enabling fast C/C ++ local applications, as well as browsers and Java? Simple Integration of technologies and extended virtual machines (such as game engines and music players.

(3) Open-apart from local C/C ++, brew also supports multiple other languages, including Java, extensible identity Language (XML), flash and other execution environments. Furthermore, because it can reside on smartphones using any mobile operating system (OS) such as palm, brew Release System (BDS) can be used) download applications written for these operating systems wirelessly and commercialize them like brew applications.

(4) scalability-third parties can write extensions for the Brew platform to provide additional functions to the application. Qualcomm ensures that brew remains open by publishing extensions and providing them to development groups.

(5) high cost efficiency-reduce development costs and shorten the product market time of equipment manufacturers. Device manufacturers can spend less time developing applications and configuring applications for different types of products, rather than investing more time in product design.

(6) security-brew protects basic telephone and wireless network operations.

2. Brew migration package

The BREW Platform promises to infinitely simplify the development and manufacture of products and services. Its core is the brew porting package. It shortens the process of integrating the BREW Platform into new equipment.
3. Brew SDK (software development kit)

The Brew SDK allows developers to use standard tools to work in familiar environments. That is to say, you can write applications used in brew-based devices without having to know the source code of the chip system and its direct relationship with the device manufacturer.

4. Brew Release System (BDS)

BDS allows operators to easily launch applications from developers to the market and coordinate settlement and payment.
Operators can adjust BDS as needed, including managing their own application release and pricing, and selecting third-party management applications, or choose Qualcomm to manage applications through the Internet of carriers and developers and release the Terms and Conditions for carriers and developers.

5. Application Type

Brew allows users to customize handheld devices only by the application they need. You only need to press a few buttons to select from a large number of applications.

Communication-instant communication, email, ringtones, and other interactive message transmission

Location- ing, browsing, transportation, and other specific positioning content

Efficiency tools-mobile synchronization office applications and utilities, improving personal efficiency

Games-interactive games between a single player and multiple players

Mobile Commerce-account balance, retail, stock trading, and other financial transactions.

Entertainment-music, video, humor, and even tracking an event

Information-flight tracking, news, weather, sports and other daily information

Extensions-third-party extensions of the powerful BREW Platform that developers can use in applications

Brew in Qualcomm wireless Internet Launchpad? Provides a set of embedded function APIs, a set of highly integrated chip set functions, system software, and plug-ins for implementing advanced Internet and multimedia functions, eliminating the need to use most additional components. If necessary, the brew environment can also be expanded by the manufacturer or other developers at any time to provide additional features available to applications. This allows powerful small local applications to access local processing and storage, so as to obtain a Client/Server solution with better performance and functionality than browser-based structures.

 

J2EE

Java 2 Micro Edition is short for Java 2. In short, it is a technology launched by Sun to apply Java to mobile communication devices, embedded devices, or consumer appliances, is the best solution for consuming products and embedded devices. While designing its specifications, the basic principle of "Creating a single development system for a variety of devices is meaningless" is followed. Therefore, the first step is to divide all embedded devices into two types: one is embedded devices with limited computing functions and limited power supply (such as PDAs and mobile phones ); the other is embedded devices with relatively better computing capability and ample power supply (such as air conditioners, refrigerators, and set-top boxes )). Because of these two differences, Java introduces a concept called configuration, and defines the embedded devices with limited computing functions and limited power in the connected limited device configuration (cldc) specification; the other device specification is the connected device configuration (CDC) specification. In other words, the concept of configuration is separated into two abstract types by all embedded devices.

1. First knowledge of j2s
Based on the traditional computer system, j2's focus is on improving consumer appliances. Java has established three layers on the original operating system of the device for modularization and scalability. They are Java Vm, configuration, and profile ). VM is responsible for compiling JAVA byte code specifications, running software on the host operating system, and simulating special software on the Java computer. Configuration is a specification used to define VM features and Java core class libraries. It uses the smallest class libraries to implement simple VM functions. Profile is based on configuration specifications. It provides additional class libraries, sets advanced features, and establishes advanced class libraries. The framework is implemented based on a specific configuration layer.

2. j2's Core
The core feature of j2's is KVM. On the VM layer, Sun first implements KVM, which means that the memory needs to be calculated only in kb when the program is running. KVM only needs 40 kb ~ 80 KB memory. At the same time, it is highly portable and suitable for 16-bit or 32-bit Proteus/CISC platforms. In the configuration layer, j2-defined two types of configuration: CDC (connected device configuration, connection-oriented device configuration) and cldc (connected limited device configuration, connection-oriented limited device configuration, the CDC requirements are kb Rom, kB RAM, broadband network, and TCP/IP protocol. The standard VM (JVM) is used ), the corresponding profiles include personal profile, car profile, and TV profile, which are mainly used for internet screen phone Reference Forum, digital video broadcasting, vehicle navigation system, and entertainment products. Cldc requires kb ~ KB memory, and the ratio of Ram to Rom can be adjusted as needed; limited energy supply (such as battery) can be adopted; narrowband network is enough, and the system must not support TCP/IP protocol. The VM is a simplified version, and standard JVM cannot be used directly. The profile corresponding to cldc includes mid profile, PDA profile, and POS/eft profile. In contrast, it is applicable to devices with two-way network connections but limited hardware resources, such as mobile phones and handheld computers. On the profile layer, j2's MIDP (mobile information device profile, mobile information device framework) is applicable to mobile phones, pagers, PDAs, and other mobile digital devices.

3. Advantages of J2EE
Traditional mobile phone software can only provide the most basic voice and short message functions. The software released later added simple additional applications, such as phone book and ringtone editing. With the development of Internet technology, mobile phones are also unwilling to lag behind. The WAP-based Internet access function is added, allowing users to access the Internet over wireless easily through mobile phones. At this stage, mobile phone manufacturers have encountered two problems: first, the software development cycle is too long. Due to the lack of an open and unified programming platform, it is impossible to transplant the program. The vendor needs to write programs for each platform separately, which will undoubtedly take a lot of time and manpower and material resources. Due to various problems, it is difficult for third-party developers to intervene, which also affects the expansion of the market. The other problem is that the access to the Internet through a browser is limited. The existing WAP function cannot directly access the internet. The Internet needs to be filtered through the gateway, and the access to WML is only allowed, instead of the mainstream HTML, and cannot display complex formats and graphics. Using online transactions increases server load, which is slow and secure. In addition, the failure to access the local storage area is also a fatal injury to the WAP function.

The emergence of j2's solves the above problems. Because the Java language runs across platforms, this feature eliminates the hassle of developers developing corresponding programs on each platform. Third-party software developers can easily intervene in the development of applications, the development cycle is greatly shortened, and dynamic download and upgrade of applications are also supported. With the HTTP Advanced Internet protocol, mobile phones can directly access all Internet Information in Client/Server mode. Different clients can access different files and access local storage areas, provides the most efficient online transactions. Mobile device manufacturers are undoubtedly looking forward to a cross-platform programming tool, and the emergence.

4. Applications of j2s
In addition to improving the existing applications of mobile phones, the agent also provides many enhancement functions, such as dictionaries, books, games, remote control appliances, and timed reminders, you can also access emails, instant messages, stocks, electronic maps, and other information.

Currently, connectable private smart information devices play an increasingly important role in our work and life. These products (including cell phones, two-way paging, personal organizer, videophone, and POS terminals) share many commonalities. Sun tries to extend the scope of use of Java by introducing the j2s technology. This versatile Java application development platform can develop many new powerful information products. Java technology allows users, service providers, and device manufacturers to use a wide range of applications as needed through physical (wired) connections or wireless connections.