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of JAVA[EBOL]
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附件1：外文资料翻译译文
J2MEJAVA领域
1介绍
20世纪70年代着计算机革命开始计算机先进软件需求增加充分利功日益增强精密计算机处理数力C编程语言逐渐成支柱程序员开发软件计算机运行样流畅
80年代程序员目睹编程语言领域次变革高潮C语言编程力已满足计算机技术发展需问题新问题造成代代编程语言新老更问题程序设计复杂计算机软件设计编写开发落硬件发展时候两种基设计概念编程语言Simula 67Smalltalk（世纪60年代末）带接编程语言未前景循序渐进步骤期间面象编程（OOP）种新编程语言谓C++程序员中掀起场风暴
1979年Bjarne Stroustrup新泽西州贝尔实验室增强C 语言具面象特点谓C++ 语言 (++C编程语言增强承载符号)C++真正提高C编程语言开始种前置语言该计划初种编译工具Stroustrup建立类概念（Simula 67Smalltalk中概念）类创建实例象类包含数成员定义象数功成员函数介绍继承概念类继承类部分全部数成员成员函数职类概念面象编程
1988年ANSI官员C++标准化
2走进JAVA
正C++作企业开发选择语言时新突破性技术万维网出现种编程语言正萌芽逐渐成熟十年互联网普通说秘密直前美国国家科学基金会（监督互联网机构）拆防止互联网商业化壁垒1991年商贸开放时互联网政府机构学术团体专利旦商业化障碍取消万维网提供服务互联网成虚拟社区中心游客免费资讯浏览数千计虚拟商店
浏览器加强万维网浏览器转换HTML编写ASCII文文件转化成互动显示功计算机编译运行浏览器HTMLHTTP兼容正确版电脑运行浏览器相HTML文件指定某特定类型计算机前闻未闻
CC++赖机器运行机器非重新编译
互联网成功重点放发展独立机器编程语言年互联网商品化科技工作者詹姆斯戈斯林帕特里克诺顿麦克谢里登花18月发展规划1995年公众发布谓OAK改名JAVAJAVA 1991年1995年期间历数次变革时候SUN公司许科技员该语言发展做出重贡献乔恩阿瑟范霍夫乔纳森佩恩耶林添佩尔分享成功喜悦
然JAVA互联网密切相关开始开发种嵌入电子器件中软件编程语言装置CPU类型众周知谓嵌入式翻译
JAVA台
JAVA团队SUN成功建立种移植性编程语言电脑程序员进行首次编程已实现成功远远超出梦想样JAVA程序进行种移植电子装置JAVA程序安装microsoft windowsUNIXmacintosh计算机运行时机完美特网部网已美国企业符合公司成效益开发应公司移植程序兴趣JAVA已证明作种成功开发机器关应程序编程语言
3JAVA虚拟机
写JAVA程序写C++程序相似程序员编写：包含指示源代码成编辑器综合发展环境中源代码进行编译JAVAC++部分方式该编译链接程中C++程序结果运行适执行机器相反JAVA编译器JAVA源代码转换成字节JAVA虚拟机（JVM）执行
机器具体指示会包括字节中相反已包括JVM属具体机器意味着该字节包含C++程序翻译指令少
分段？
4未世界：J2ME
JAVA消费工业产品中作种编程语言创建程序嵌入式系统微机发现开始控制汽车家电器微机20世纪90年代初开发团队SUN工作利JAVA解决幼稚嵌入式电脑市场编程需种努力更侧重互联网吸引力机会
世纪交年机会已解决种新便携式通信带设备机会语音通信设备语音文通信设备便携式电子电话簿演变成数码助理时候芯片制造商推出新产品目桌型电脑转移计算力移动型电脑控制燃气水泵电缆电视盒组合电器
步演变JAVA时机合理JAVA 额外空气污染指数加强SUN公司该组JAVA 组织化翻译
计划拆均采JAVA编程语言JAVA虚拟机嵌入式系统微机设备剥离JAVAAPIJVM低限度编码须提供情报设备资源方面限制强加硬件设计必努力结果J2MEJ2ME减少JAVA APIJAVA虚拟机设计运作稀疏资源新品种嵌入式计算机微机版
5组织J2ME
传统计算设备需标准相硬件配置显示器键盘鼠标量记忆永久储存中新代计算设备缺乏硬件配置连续性设备具显示屏永久储存键盘鼠标中计算设备记忆提供情况致缺乏统标准硬件配置间型计算设备构成项艰巨挑战JAVA 组织化翻译
计划JVMJ2ME型计算设备制定标准
许种J2ME计算设备包括视电话数字机顶盒线电视手机数字助理面挑战JAVA 组织化翻译
计划建立标准计算设备实施JAVA标准
6J2ME线设备
着手机等线设备量出现功逐渐完善运行样设备软件求量越越消费者企业扩移动通信设备功传统语音通信渡类似笔记电脑电脑功传送接收电子邮件存储检索资料执行精密计算玩游戏
开发商移动通信设备制造商移动网络供应商现正急欲填补方面需求严重障碍：移动通信设备利许应台营调整代码设备开发代码法运行设备移动通信设备缺乏标准应台作业系统应开发移动通信设备促进济发展险
缺乏标准没新计算技术开发传统意义硬件设备制造商尝试产品遍市场执行专标准作事实业界标准许暴发户成功情况微软样时候业界领袖
组成财团例JAVA 组织化翻译
计划集体制定种标准
线应协议（WAP）行动网际网路坛成初步创建线技术标准产业集团WAP 坛创造移动通信设备标准称thewap标准thewap标准提高HTMLXMLTCPIP 组成部分标准线标记语言规范组成融合HTMLXMLwmlscript 种剥夺式版JAVAscript
7J2ME 应翻译
程序
J2ME应程序称MIDLET运行实现JVMMIDP移动通信设备鼓励开发商投资时间金钱建设移动通信设备需担心该应设备赖风险J2ME会视更换WAP规格两者互补技术开发商申请根客户求基础继续wmlwmlscript开发商转J2ME较重客户需移动通信设备进行复杂处理
附件2：外文原文（复印件）
JAVA 2 Micro Edition and The World of JAVA
1 Introduction
The computer revolution of the 1970s increased the demand for sophisticated computer soft
ware to take advantage of the everincreasing capacity of computers to process data
The C programming language became the linchpin that enabled programmers tobuildsoftware that was just as robust as the computer it ran on
As the 1980s approached programmers were witnessing another spurt in the evolutionof programming language Computer technology advanced beyond the capabilities of the C programming language The problem wasn’t new It occurred previously and caused the demise of generations of programming languages The problem was thatprograms were becoming too complicated to design write and manage to keep up with the capabilities of computers It was around this time that a design concept based on Simula 67 and Smalltalk (from the late 1960s) movedprogramming to the next evolutionary step This was the period when objectoriented programming (OOP) and with it a new programming language
called C++ took programmers bystorm
In 1979 Bjarne Stroustrup of Bell Laboratories in New Jersey enhanced the Cprogramming language to include objectoriented features He called the language C++ (The ++ is the incremental operator in the C programming language) C++ is truly an enhancement of the C programming language and it began as a preprocessor language that was translated into C syntax before the program was processed by the compilerStroustrup built on the concept of a class (taken from Simula 67 and Smalltalk) from which instances of objects are created A class contains data members and member functions that define an object’s data and functionality He also introduced the concept of inheritance which enabled a class to inherit some or alldata members and member functions from one or more other classes—all of which complements the concepts of objectoriented programmingBy 1988 ANSI officials standardized Stroustrup’s C++ specification
2 Enter JAVA
Just as C++ was becoming the language of choice for building industrialstrength applications another growth spurt in the evolution of programming language was budding fertilized by the latest disruptive technology—the World Wide WebThe Internethad been a wellkept secret for decades before the National Science Foundation (who oversaw the Internet) removed barriers that prevented commercialization Until 1991 when it was opened to commerce the Internet was the almostexclusive domain ofgovernment agencies and the academic community Once the barrier to commercialization was lifted the World Wide Web—one of several services offered on the Internet— became a virtual community center where visitors could get free information about practically anything and browse through thousandsof virtual stores
Browsers power the World Wide WebA browser translates ASCII text files written in HTML into an interactive display that can be interpreted on any machine As long as the browser is compatible with the correct version of HTML and HTTP impl
ementation any computer running the browser can use the same HTML document without having to modify it for a particular type of computer whichwas something unheard of at the time Programs written in C or C++ are machine dependent and cannot run on a different
machine unless the program is recompiled
The success of the Internet gave renewed focus to developing a machineindependent programming language And the same year the Internet was commercialized five technologists at SUN Microsystems set out to do just that James GoslingPatrick Naughton ChrisWarth Ed Frank and Mike Sheridan spent 18 months developingthe programming language they called Oak which was renamed JAVA when this new language made its debut in 1995 JAVA went through numerous iterations between 1991 and 1995 during which time many other technologists at SUN made substantialcontributions to the language These included Bill Joy Arthur van Hoff Jonathan Payne Frank Yelin and Tim Lindholm
Although JAVA is closely associated with the Internet it was developed as a language for programming software that could be embedded into electronic devicesregardless of the type of CPU used by the device This is known as the EmbeddedJAVA platform and is in continuous use today for closed systems
The JAVA team from SUN succeeded in creating a portable programming languagesomething that had eluded programmers since computers were first programmed Their success however was far beyond their wildest dreams The same concept used to make JAVA programs portable to electronic devices also could be used to makeJAVA programs run on computers running Microsoft Windows UNIX andMacintoshTiming was perfect The Internetintranet had whetted corporate America’s appetite for costeffective portable programs that could replace missioncriticalapplications within the corporation And JAVA had proven itself as a programming language used to successfully develop machineindependent applications
3 JAVA Virtual MachineWriting
JAVA programs is similar to writing C++ programsin that the programmer writes source code that contains instructions into an editoror in an integrated developmentenvironment and then the source code is compiledHowever that’s where JAVA andC++part ways The compiling and linking processof a C++ program results in an executablethat can be run on an appropriatemachineIn contrast the JAVA compiler converts
JAVAsource code into bytecode that is executed by the JAVA Virtual Machine (JVM)
Machinespecific instructions are not included in bytecode Instead they alreadyreside in the JVM which is machine specific This means that the bytecode might contain fewer instructions that need to be translated than a comparable C++program
Although the JAVA compiler generates bytecode that must be interpreted by theJVMat run time the number of instructions that need translation are usually minimal andhave already been optimized by the JAVA compiler4 Back to the Future J2ME Remember that JAVA began as a programming language to create programs for embedded systems—microcomputers found in consumer and industrial products such as
those used to control automobiles and appliances The development team at SUNworked on JAVA in the early 1990s to address the programming needs of the fledgling embedded computer market but that effort was sidetracked by more compelling opportunities presented by the Internet
As those opportunities were addressed a new breed of portable communicationsdevices opened other opportunities at the turn of the century Cell phones expanded
4 J2ME
The CompleteReference from voice communications devices to voice and text communications devices Pocket electronic telephone directories evolvedinto personal digital assistants Chipmakers were releasing new products at this time that weredesigned to transfer computing power from a desktop computer intomobile small computers that controlled gas pumps cable television boxes and an assortment of other appliances
The time was right for the next evolution of JAVA However instead of beefing up JAVA with additional APIs the team at SUN along with the JAVA community process Program dismantled both the JAVA programming language and the JAVAVirtual Machine Theystripped down JAVA APIs and the JVM to the minimum coding required to provideintelligence to embedded systems and microcomputer devices This was necessary because of resource constraints imposed upon the hardwaredesign of these devices Theresult of their efforts is J2ME J2ME is a reduced version of the
JAVA API and JAVA Virtual Machine that is designed to operate withinthe sparse resources available in the new breed of embedded computers and microcomputers
5 How J2ME Is Organized
Traditional computing devices use fairly standard hardware configurations such as a display keyboardmouse and large amounts of memory and permanent storageHowever the new breed of computing devices lacks hardware configuration continuity among devices Some devices don’t have a display permanent storage keyboardor mouse And memory availability is inconsistent among small computing devices The lack of uniform hardware configuration among the small computing devices poses a formidable challenge for the JAVA community process Programwhich is chargedwith developing standards for the JVM and the J2ME for smallcomputing devices
J2ME must service many different kinds of small computing devices includingscreenphones digital settop boxes used for cable television cell phones and personal digital assistants The challenge for the JAVA community process Program is to develop a JAVA standard that can be implemented on small computing devices that have nonstandard hardware configurations The JAVA community process Program has used a twofold approach to addressing the needs of small computing devices First they defined the JAVA runtime environment and core classes that operate on each device This is referred to as the configuration A configuration defines the JAVA Virtual Machine for a particular small computing device There are two configurations one for handheld devices and the other for plugin devices Next the JAVA community process Program defined a profile for categories of smallcomputing devices A profile consists of classes that enable developers to implement features found on a related group of small computing devices
6 J2ME and Wireless Devices
With the dramatic increase and sophistication of mobile communications devicessuchas cell phones came demand for applications that can run on those devices Consumers and corporations want to expand mobile communications devices from voice communications to applications traditionally found on laptops and PCs They want tosend and receive
email store and retrieve personal information perform sophisticated calculations and play games
Developers mobile communications device manufacturers and mobile network p roviders are anxious to fill this need but there is a serious hurdle mobile communications devices utilize a number of different application platforms and operating systemsWithout tweaking the code an application written for one device cannot runon another device
Mobile communications devices lack a standard application platform and operating system which has made developing applications for mobile communications devices a risky economic venture for developersThe lack of standards is nothing new to computing or to any developing technology
Traditionally manufacturers of hardware devices try to corner the market and enforce their own proprietary standard as the de facto standard for the industry Usually one upstart succeeds as in the case of Microsoft Other times industry leadersform aconsortium such as the JAVA community process Program to collectively develop a standard
The Wireless Application Protocol (WAP) forum became the initial industry group that set out to create standards for wireless technology Ericsson Motorola Nokia and Unvired Planet formed theWAP forum in 1997 and it has since grown to include nearly all mobile device manufacturers mobile network providers and developersThe WAP forum created mobile communications device standards referred to astheWAP standard
The WAP standard is an enhancement of HTML XML and TCPIP One element of this standard is the Wireless Markup Language specification which consists of ablend of HTML and XML and is used by developers to create documents thatcan be displayed by a microbrowser A microbrowser is a diminutive webbrowser that operates on a mobile communications deviceThe WAP standard also includes specifications for aWireless Telephony ApplicationInterface (WTAI) specification and the WMLScript specification WTAI is used to create an interface forapplications that runon a mobile communications devic
e WMLScript is a strippeddownversion of JAVAScript
7 J2ME applications
J2ME applications referred to as a MIDlet can run on practically any mobile communications device that implements a JVM and MIDP This encourages developers toinvest time and money in building applications for mobile communications devices without the risk that the application is device dependent However J2ME isn’tseen as a replacement for the WAP specification because both are complementary technologies Developers whose applications are lightclient based continueto use WML andWMLScript Developers turn to J2ME for heavier clients that require sophisticated processing on the mobile communications device
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毕业设计(文)外文资料翻译
系： 计算机系
专 业： 计算机科学技术
姓 名：
学 号：
(外文写)
外文出处：JAVA 2 Micro Edition and the World
of JAVA[EBOL]
l
附 件： 1外文资料翻译译文2外文原文
签名：
年 月 日
注：请该封面附件装订成册
附件1：外文资料翻译译文
J2MEJAVA领域
1介绍
20世纪70年代着计算机革命开始计算机先进软件需求增加充分利功日益增强精密计算机处理数力C编程语言逐渐成支柱程序员开发软件计算机运行样流畅
80年代程序员目睹编程语言领域次变革高潮C语言编程力已满足计算机技术发展需问题新问题造成代代编程语言新老更问题程序设计复杂计算机软件设计编写开发落硬件发展时候两种基设计概念编程语言Simula 67Smalltalk（世纪60年代末）带接编程语言未前景循序渐进步骤期间面象编程（OOP）种新编程语言谓C++程序员中掀起场风暴
1979年Bjarne Stroustrup新泽西州贝尔实验室增强C 语言具面象特点谓C++ 语言 (++C编程语言增强承载符号)C++真正提高C编程语言开始种前置语言该计划初种编译工具Stroustrup建立类概念（Simula 67Smalltalk中概念）类创建实例象类包含数成员定义象数功成员函数介绍继承概念类继承类部分全部数成员成员函数职类概念面象编程
1988年ANSI官员C++标准化
2走进JAVA
正C++作企业开发选择语言时新突破性技术万维网出现种编程语言正萌芽逐渐成熟十年互联网普通说秘密直前美国国家科学基金会（监督互联网机构）拆防止互联网商业化壁垒1991年商贸开放时互联网政府机构学术团体专利旦商业化障碍取消万维网提供服务互联网成虚拟社区中心游客免费资讯浏览数千计虚拟商店
浏览器加强万维网浏览器转换HTML编写ASCII文文件转化成互动显示功计算机编译运行浏览器HTMLHTTP兼容正确版电脑运行浏览器相HTML文件指定某特定类型计算机前闻未闻
CC++赖机器运行机器非重新编译
互联网成功重点放发展独立机器编程语言年互联网商品化科技工作者詹姆斯戈斯林帕特里克诺顿麦克谢里登花18月发展规划1995年公众发布谓OAK改名JAVAJAVA 1991年1995年期间历数次变革时候SUN公司许科技员该语言发展做出重贡献乔恩阿瑟范霍夫乔纳森佩恩耶林添佩尔分享成功喜悦
然JAVA互联网密切相关开始开发种嵌入电子器件中软件编程语言装置CPU类型众周知谓嵌入式翻译
JAVA台
JAVA团队SUN成功建立种移植性编程语言电脑程序员进行首次编程已实现成功远远超出梦想样JAVA程序进行种移植电子装置JAVA程序安装microsoft windowsUNIXmacintosh计算机运行时机完美特网部网已美国企业符合公司成效益开发应公司移植程序兴趣JAVA已证明作种成功开发机器关应程序编程语言
3JAVA虚拟机
写JAVA程序写C++程序相似程序员编写：包含指示源代码成编辑器综合发展环境中源代码进行编译JAVAC++部分方式该编译链接程中C++程序结果运行适执行机器相反JAVA编译器JAVA源代码转换成字节JAVA虚拟机（JVM）执行
机器具体指示会包括字节中相反已包括JVM属具体机器意味着该字节包含C++程序翻译指令少
分段？
4未世界：J2ME
JAVA消费工业产品中作种编程语言创建程序嵌入式系统微机发现开始控制汽车家电器微机20世纪90年代初开发团队SUN工作利JAVA解决幼稚嵌入式电脑市场编程需种努力更侧重互联网吸引力机会
世纪交年机会已解决种新便携式通信带设备机会语音通信设备语音文通信设备便携式电子电话簿演变成数码助理时候芯片制造商推出新产品目桌型电脑转移计算力移动型电脑控制燃气水泵电缆电视盒组合电器
步演变JAVA时机合理JAVA 额外空气污染指数加强SUN公司该组JAVA 组织化翻译
计划拆均采JAVA编程语言JAVA虚拟机嵌入式系统微机设备剥离JAVAAPIJVM低限度编码须提供情报设备资源方面限制强加硬件设计必努力结果J2MEJ2ME减少JAVA APIJAVA虚拟机设计运作稀疏资源新品种嵌入式计算机微机版
5组织J2ME
传统计算设备需标准相硬件配置显示器键盘鼠标量记忆永久储存中新代计算设备缺乏硬件配置连续性设备具显示屏永久储存键盘鼠标中计算设备记忆提供情况致缺乏统标准硬件配置间型计算设备构成项艰巨挑战JAVA 组织化翻译
计划JVMJ2ME型计算设备制定标准
许种J2ME计算设备包括视电话数字机顶盒线电视手机数字助理面挑战JAVA 组织化翻译
计划建立标准计算设备实施JAVA标准
6J2ME线设备
着手机等线设备量出现功逐渐完善运行样设备软件求量越越消费者企业扩移动通信设备功传统语音通信渡类似笔记电脑电脑功传送接收电子邮件存储检索资料执行精密计算玩游戏
开发商移动通信设备制造商移动网络供应商现正急欲填补方面需求严重障碍：移动通信设备利许应台营调整代码设备开发代码法运行设备移动通信设备缺乏标准应台作业系统应开发移动通信设备促进济发展险
缺乏标准没新计算技术开发传统意义硬件设备制造商尝试产品遍市场执行专标准作事实业界标准许暴发户成功情况微软样时候业界领袖
组成财团例JAVA 组织化翻译
计划集体制定种标准
线应协议（WAP）行动网际网路坛成初步创建线技术标准产业集团WAP 坛创造移动通信设备标准称thewap标准thewap标准提高HTMLXMLTCPIP 组成部分标准线标记语言规范组成融合HTMLXMLwmlscript 种剥夺式版JAVAscript
7J2ME 应翻译
程序
J2ME应程序称MIDLET运行实现JVMMIDP移动通信设备鼓励开发商投资时间金钱建设移动通信设备需担心该应设备赖风险J2ME会视更换WAP规格两者互补技术开发商申请根客户求基础继续wmlwmlscript开发商转J2ME较重客户需移动通信设备进行复杂处理
附件2：外文原文（复印件）
JAVA 2 Micro Edition and The World of JAVA
1 Introduction
The computer revolution of the 1970s increased the demand for sophisticated computer soft
ware to take advantage of the everincreasing capacity of computers to process data
The C programming language became the linchpin that enabled programmers tobuildsoftware that was just as robust as the computer it ran on
As the 1980s approached programmers were witnessing another spurt in the evolutionof programming language Computer technology advanced beyond the capabilities of the C programming language The problem wasn’t new It occurred previously and caused the demise of generations of programming languages The problem was thatprograms were becoming too complicated to design write and manage to keep up with the capabilities of computers It was around this time that a design concept based on Simula 67 and Smalltalk (from the late 1960s) movedprogramming to the next evolutionary step This was the period when objectoriented programming (OOP) and with it a new programming language
called C++ took programmers bystorm
In 1979 Bjarne Stroustrup of Bell Laboratories in New Jersey enhanced the Cprogramming language to include objectoriented features He called the language C++ (The ++ is the incremental operator in the C programming language) C++ is truly an enhancement of the C programming language and it began as a preprocessor language that was translated into C syntax before the program was processed by the compilerStroustrup built on the concept of a class (taken from Simula 67 and Smalltalk) from which instances of objects are created A class contains data members and member functions that define an object’s data and functionality He also introduced the concept of inheritance which enabled a class to inherit some or alldata members and member functions from one or more other classes—all of which complements the concepts of objectoriented programmingBy 1988 ANSI officials standardized Stroustrup’s C++ specification
2 Enter JAVA
Just as C++ was becoming the language of choice for building industrialstrength applications another growth spurt in the evolution of programming language was budding fertilized by the latest disruptive technology—the World Wide WebThe Internethad been a wellkept secret for decades before the National Science Foundation (who oversaw the Internet) removed barriers that prevented commercialization Until 1991 when it was opened to commerce the Internet was the almostexclusive domain ofgovernment agencies and the academic community Once the barrier to commercialization was lifted the World Wide Web—one of several services offered on the Internet— became a virtual community center where visitors could get free information about practically anything and browse through thousandsof virtual stores
Browsers power the World Wide WebA browser translates ASCII text files written in HTML into an interactive display that can be interpreted on any machine As long as the browser is compatible with the correct version of HTML and HTTP impl
ementation any computer running the browser can use the same HTML document without having to modify it for a particular type of computer whichwas something unheard of at the time Programs written in C or C++ are machine dependent and cannot run on a different
machine unless the program is recompiled
The success of the Internet gave renewed focus to developing a machineindependent programming language And the same year the Internet was commercialized five technologists at SUN Microsystems set out to do just that James GoslingPatrick Naughton ChrisWarth Ed Frank and Mike Sheridan spent 18 months developingthe programming language they called Oak which was renamed JAVA when this new language made its debut in 1995 JAVA went through numerous iterations between 1991 and 1995 during which time many other technologists at SUN made substantialcontributions to the language These included Bill Joy Arthur van Hoff Jonathan Payne Frank Yelin and Tim Lindholm
Although JAVA is closely associated with the Internet it was developed as a language for programming software that could be embedded into electronic devicesregardless of the type of CPU used by the device This is known as the EmbeddedJAVA platform and is in continuous use today for closed systems
The JAVA team from SUN succeeded in creating a portable programming languagesomething that had eluded programmers since computers were first programmed Their success however was far beyond their wildest dreams The same concept used to make JAVA programs portable to electronic devices also could be used to makeJAVA programs run on computers running Microsoft Windows UNIX andMacintoshTiming was perfect The Internetintranet had whetted corporate America’s appetite for costeffective portable programs that could replace missioncriticalapplications within the corporation And JAVA had proven itself as a programming language used to successfully develop machineindependent applications
3 JAVA Virtual MachineWriting
JAVA programs is similar to writing C++ programsin that the programmer writes source code that contains instructions into an editoror in an integrated developmentenvironment and then the source code is compiledHowever that’s where JAVA andC++part ways The compiling and linking processof a C++ program results in an executablethat can be run on an appropriatemachineIn contrast the JAVA compiler converts
JAVAsource code into bytecode that is executed by the JAVA Virtual Machine (JVM)
Machinespecific instructions are not included in bytecode Instead they alreadyreside in the JVM which is machine specific This means that the bytecode might contain fewer instructions that need to be translated than a comparable C++program
Although the JAVA compiler generates bytecode that must be interpreted by theJVMat run time the number of instructions that need translation are usually minimal andhave already been optimized by the JAVA compiler4 Back to the Future J2ME Remember that JAVA began as a programming language to create programs for embedded systems—microcomputers found in consumer and industrial products such as
those used to control automobiles and appliances The development team at SUNworked on JAVA in the early 1990s to address the programming needs of the fledgling embedded computer market but that effort was sidetracked by more compelling opportunities presented by the Internet
As those opportunities were addressed a new breed of portable communicationsdevices opened other opportunities at the turn of the century Cell phones expanded
4 J2ME
The CompleteReference from voice communications devices to voice and text communications devices Pocket electronic telephone directories evolvedinto personal digital assistants Chipmakers were releasing new products at this time that weredesigned to transfer computing power from a desktop computer intomobile small computers that controlled gas pumps cable television boxes and an assortment of other appliances
The time was right for the next evolution of JAVA However instead of beefing up JAVA with additional APIs the team at SUN along with the JAVA community process Program dismantled both the JAVA programming language and the JAVAVirtual Machine Theystripped down JAVA APIs and the JVM to the minimum coding required to provideintelligence to embedded systems and microcomputer devices This was necessary because of resource constraints imposed upon the hardwaredesign of these devices Theresult of their efforts is J2ME J2ME is a reduced version of the
JAVA API and JAVA Virtual Machine that is designed to operate withinthe sparse resources available in the new breed of embedded computers and microcomputers
5 How J2ME Is Organized
Traditional computing devices use fairly standard hardware configurations such as a display keyboardmouse and large amounts of memory and permanent storageHowever the new breed of computing devices lacks hardware configuration continuity among devices Some devices don’t have a display permanent storage keyboardor mouse And memory availability is inconsistent among small computing devices The lack of uniform hardware configuration among the small computing devices poses a formidable challenge for the JAVA community process Programwhich is chargedwith developing standards for the JVM and the J2ME for smallcomputing devices
J2ME must service many different kinds of small computing devices includingscreenphones digital settop boxes used for cable television cell phones and personal digital assistants The challenge for the JAVA community process Program is to develop a JAVA standard that can be implemented on small computing devices that have nonstandard hardware configurations The JAVA community process Program has used a twofold approach to addressing the needs of small computing devices First they defined the JAVA runtime environment and core classes that operate on each device This is referred to as the configuration A configuration defines the JAVA Virtual Machine for a particular small computing device There are two configurations one for handheld devices and the other for plugin devices Next the JAVA community process Program defined a profile for categories of smallcomputing devices A profile consists of classes that enable developers to implement features found on a related group of small computing devices
6 J2ME and Wireless Devices
With the dramatic increase and sophistication of mobile communications devicessuchas cell phones came demand for applications that can run on those devices Consumers and corporations want to expand mobile communications devices from voice communications to applications traditionally found on laptops and PCs They want tosend and receive
email store and retrieve personal information perform sophisticated calculations and play games
Developers mobile communications device manufacturers and mobile network p roviders are anxious to fill this need but there is a serious hurdle mobile communications devices utilize a number of different application platforms and operating systemsWithout tweaking the code an application written for one device cannot runon another device
Mobile communications devices lack a standard application platform and operating system which has made developing applications for mobile communications devices a risky economic venture for developersThe lack of standards is nothing new to computing or to any developing technology
Traditionally manufacturers of hardware devices try to corner the market and enforce their own proprietary standard as the de facto standard for the industry Usually one upstart succeeds as in the case of Microsoft Other times industry leadersform aconsortium such as the JAVA community process Program to collectively develop a standard
The Wireless Application Protocol (WAP) forum became the initial industry group that set out to create standards for wireless technology Ericsson Motorola Nokia and Unvired Planet formed theWAP forum in 1997 and it has since grown to include nearly all mobile device manufacturers mobile network providers and developersThe WAP forum created mobile communications device standards referred to astheWAP standard
The WAP standard is an enhancement of HTML XML and TCPIP One element of this standard is the Wireless Markup Language specification which consists of ablend of HTML and XML and is used by developers to create documents thatcan be displayed by a microbrowser A microbrowser is a diminutive webbrowser that operates on a mobile communications deviceThe WAP standard also includes specifications for aWireless Telephony ApplicationInterface (WTAI) specification and the WMLScript specification WTAI is used to create an interface forapplications that runon a mobile communications devic
e WMLScript is a strippeddownversion of JAVAScript
7 J2ME applications
J2ME applications referred to as a MIDlet can run on practically any mobile communications device that implements a JVM and MIDP This encourages developers toinvest time and money in building applications for mobile communications devices without the risk that the application is device dependent However J2ME isn’tseen as a replacement for the WAP specification because both are complementary technologies Developers whose applications are lightclient based continueto use WML andWMLScript Developers turn to J2ME for heavier clients that require sophisticated processing on the mobile communications device
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