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This paper proposes a systematic approach to optimize the code layout of a Java ME virtual machine for an embedded system with a cache-sensitive architecture. A practice example is to run JVM directly (execution-in-place) in NAND flash memory, for which cache miss penalty is too high to endure. The refined virtual machine generated cache misses 96% less than the original version. We developed a mathematical approach helping to predict the flow of the interpreter inside the virtual machine. This approach analyzed both the static control flow graph and the pattern of bytecode instruction streams, since we found the input sequence drives the program flow of the virtual machine interpreter. Then we proposed a rule to model the execution flows of Java instructions of real applications. Furthermore, we used a graph partition algorithm as a tool to deal with the mathematical model, and this finding helped the relocation process to move program blocks to proper memory pages. The refinement approach dramatically improved the locality of the virtual machine thus reduced cache miss rates. Our technique can help Java ME-enabled devices to run faster and extend longer battery life. The approach also brings potential for designers to integrate the XIP function into System-on-Chip thanks to lower demand for cache memory. [ABSTRACT FROM AUTHOR]

As applications for small embedded mobile devices are getting larger and more complex, it becomes inevitable to adopt more advanced software engineering methods from the field of desktop application development. Aspect-oriented programming (AOP) is a promising approach due to its advanced modularization capabilities. However, existing AOP languages tend to add a substantial overhead in both execution time and code size which restricts their practicality for small devices with limited resources. In this paper, we present optimizations for aspect-oriented mechanisms at the level of the virtual machine. Our experiments show that these optimizations yield a considerable performance gain along with a reduction of the code size. Thus, our optimizations establish the base for using advanced aspect-oriented modularization techniques for developing Java applications on small embedded devices. [ABSTRACT FROM AUTHOR]