Java Card Virtual Machine Research And Optimization

With the rapid development of information technology, a large number of scientific and technological products emerged in people’s daily life, and the goal of pursuit of a higher quality of life puts forward higher requirements for technology products. Since the Java Card technology has been created, it has many advantages such as platform-independent, multi-application on single card, dynamically install and delete the applet and a higher security mechanism etc. These features lead to Java Card been widely used in all aspects of the private information store area, authentication identify, digital money and other communications area. Java Card technology is a combination of the original COS smart cards and Java technology, including two parts of the Java Card Virtual Machine and Java language development. JCVM provided a reliable support in the aspects of bytecode applet execution, memory management and exception handling.Smart card technology development in Europe and United States is early than China. After a long period of development, has become a mature technology system, and implemented a strict technology export control, that leads to many domestic operators have to spend a lot of copyright royalties to introduction of foreign technology. Although our smart card technology has developed rapidly in recent years, but still in a backward state, which has been developed for the produce a severe impact on our country’s development and daily life, so develop the smart card technology withs independent intellectual property rights will produce a practical significance.In this paper, we analyze the structure of the Java Card system and studied the JCVM model and Applet development process. The main content of this paper as fellow:1. In terms of bytecode resolution, in order to improved the efficiency of space utilization of the system, we analyze applet development process and combined with the JCVM on-card resolution and off-card resolution collaborative ideas, design a static bytecode resolution optimization scheme based on the collaboration between dynamic resolution and static resolution, which reduced system resource consumption and improved JCVM run speed.2.In the aspect of interpreter, in order to improve the matching rate between the instruction and program code during the runtime of interpreted execution, we presented interpreter optimization scheme based on some translation direct threaded ideas, on the basis of anslysis JCVM interpreter structure and combined with the property of instruction set.3. For the part of garbage collection, we analysis system storage management mechanism in connection with object-oriented features of the Java language, designed the object management mechanism. Compared the classic garbage collection algorithm and designed a new garbage collection algorithm based on the generational ideas, in which implemented replication processes based on the RAM buffering mechanism, which reduces the number of write operations of EEPROM memory and extended the storage life.Through the summary of the full abstract, problem remained in system is analysised, and now there are still some problems and require further in-depth study.