【導(dǎo)讀】20世紀(jì)70年代以來隨著計算機革命的開始，對計算機先進軟件的需求大大增加，從而可以充分利用功能日益增強的精密的計算機的處理數(shù)據(jù)的能力。80年代以來，程序員又目睹了編程語言領(lǐng)域的又一次變革的高潮。能力已經(jīng)不能滿足計算機的技術(shù)發(fā)展的需要。這問題并不是新問題。的設(shè)計，編寫和開發(fā)落后于硬件的發(fā)展。C++在程序員中掀起了一場風(fēng)暴。面向?qū)ο蟮奶攸c即所謂的C++語言。一個類包含數(shù)據(jù)成員和定義對象數(shù)據(jù)和功能的成員函數(shù)。1988年由ANSI官員將C++標(biāo)準(zhǔn)化?？萍既藛T對該語言的發(fā)展做出了重大貢獻。機器的具體指示，則不會包括在字節(jié)中。在這時候，芯片制造商所推出的新產(chǎn)品，其目的是為了從桌上型電腦轉(zhuǎn)移計。為下一步的演變的JAVA的時機是合理的。缺乏統(tǒng)一標(biāo)準(zhǔn)的硬件配置之間的小型計算設(shè)備的構(gòu)成是一項艱巨的挑戰(zhàn)JAVA. 組織化的計劃則是為JVM和J2ME的小型計算設(shè)備制定標(biāo)準(zhǔn)。件的要求量也越來越大。消費者和企業(yè)都要擴大移動通信設(shè)備的功能，使其

　　

【正文】 r plugin devices. Next, the JAVA munity process Program defined a profile for categories of smallputing devices. A profile consists of classes that enable developers to implement features found on a related group of small puting devices. 6 J2ME and Wireless Devices With the dramatic increase and sophistication of mobile munications devicessuchas cell phones came demand for applications that can run on those devices. Consumers and corporations want to expand mobile munications devices from voice communications to applications traditionally found on laptops and PCs. They want tosend and receive , store and retrieve personal information, perform sophisticated calculations, and play games. Developers, mobile munications device manufacturers, and mobile work p roviders are anxious to fill this need, but there is a serious hurdle: mobile munications devices utilize a number of different application platforms and operating system tweaking the code, an application written for one device cannot runon another device. Mobile munications devices lack a standard application platform and operating system, which has made developing applications for mobile munications devices a risky economic venture for 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 munity 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 Pla formed theWAP forum in 1997, and it has since grown to include nearly all mobile device manufacturers, mobile work providers, and developers.The WAP forum created mobile munications device standards referred to astheWAP standard. The WAP standard is an enhancement of HTML, XML, and TCP/IP. 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 munications 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 munications device. WMLScript is a strippeddownversion of JAVAScript. 7 J2ME applications J2ME applications referred to as a MIDlet can run on practically any mobile munications device that implements a JVM and MIDP. This encourages developers toinvest time and money in building applications for mobile munications devices without the risk that the application is device dependent. However, J2ME isn’tseen as a replacement for the WAP specification because both are plementary 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 munications device.