Based On The Embedded Operating System Re Works The Transplantation Of The Java Virtual Machine

With the continuous development of mobile communication and mobile terminals more and more abundant, the need of softwares becomes higher and higher. For specific operating system, it takes a lot of resources to develop a lot of high quality application softwares. A simple solution is to preset a middleware in the operating system.As a kind of middleware platform, J2ME has been widely accepted. And the J2ME applications for handheld mobile terminals also provide plenty of embedded softwares. As a kind of embedded system, Re Works needs JAVA middleware as one of its indispensable functions.This paper introduced the characteristics of embedded system first. Then, the structure of embedded Java Virtual Machine KVM is analysed, and disclose the mechanism of embedded Java internal running system. After that, a practical methodology of porting KVM is proposed, which includes transplantation of graphics level of and operating system level. And as a result, a KVM is implemented based on the graphic system of DirectFB running on the operating system Re Works, realizing the execution of the J2ME programs, downloading on the air and the requirement of real-time. The main research results of this text have four respects:(1) Java is supported on Re Works platform. J2ME standard is supported, including CLDC1.0 and MIDP2.0, which is able to run MIDlet applications, and showing Chinese OTA(on the air) downloading, and touch screen is supported.(2) Considered of the actual characteristics, porting methods are put forward, including graphics system porting and operating system porting. According to the characteristics of complex graphics system, a method is taken that rewrites the API, and compiles, runs and tests altogether. According to the characteristics of supporting the POSIX standard, a method is taken that compiles after modifies all the functions. Experiment results show that these methods are effective.(3) A series of major issues are solved, including KVM efficiency problem, graphics system showing, replacing functions that Re Works does not support, as well as the problem that developing board may lock-up when downloading. Among those problems, the solution of the efficiency problems is of great significance for the project.