Research And Implementation Of Debug Agent Technology In J2ME Porting

J2ME is a popular software development platform on terminal devices within wireless telecommunications domain. The key technique in J2ME is laying a Java Virtual Machine software, which is responsible for interpreting and executing the Java applications, upon the hardware and operating system platform in embedded system devices. This Java Virtual Machine, which is usually not more than 128 kilobytes due to the constraints of terminal resources, is called KVM. KVM is implemented tightly with the bottom hardware and software platform in devices and is not visible to application users. The configuration layer and profiles layer are defined on top of KVM by SUN to implement the cross-platform characteristic of J2ME and this two layers provide universal Application Programming Interfaces(APIs) and Java class libraries for the top applications.The application developers often use a third-party Integrated Development Environment(IDE) tool and it is very important to make the IDE capable of supporting source-level debugging of J2ME applications on devices. In order to saving the memory resources in embedded devices, Sun corporation bring forward the Debug Agent technology, i.e. a Debug Agent program is interposed between the IDE and the KVM, which is an independent thread running on the workstation platform. The Debug Agent allows many of the memory consuming of the KVM when processing the debugging instructions to be processed on the developer's workstation, therefore reducing the memory overhead that the debugging operations have on the KVM.The topic of this paper comes from iDEN SDK project in Motorola Nanjing Software Center. IDEN series SDK are the Windows J2ME SDK for iDEN series Java mobile phones used by the iDEN customers and are developed through cross-platform porting from the embedded J2ME implementation in iDEN phones to Windows platform. IDEN SDK can be integrated with certain third-party Java IDEs and support the source-level debugging function of J2ME applications by implementing the Debug Agent technology.At the beginning of this paper, we introduce the J2ME architecture, development of J2ME applications and the requirements on J2ME source-level debugging. Afterwards, do an in-depth research on the the Debug Agent technology under J2ME platform. Following we discuss the iDEN SDK developed through the porting method and expound the implementation of the Debug Agent technology in iDEN SDK. At last, we study the algorithms of some key debug functions and propose the improvements.