| Modularity is a new design ideology based on the development of traditional design. In our times for the characteristics of innovation, fast and personalized, it is the inevitable trend that modularity meets the structural and functional complexity of product or service and diversity of consumption. With the development of modular trends, it will continue to deepen the transformation of organizational model and the change of industrial structure.Our intention is to try to optimize system modularity by adjusting system structure from the perspective of modularity. One of our aims is to explore whether actual software structures can be optimized. The second is to wish to obtain some laws about software evolution by research results and provide some guidance suggestions for the design of software architecture.In order to study the modularity of system structure and analyze the law of system architecture evolution, we defined the modular index which measured the system modularity from different perspectives in this paper. Then we adopted the quantitative calculation method, established some optimization models, got some methods of module partition and evaluated and analyzed the effects of the different divisions.Finally, we used Java Development Kit (JDK) as an example, analyzed the modular structures of different JDK versions, interpreted the results, drew patterns and trends in the evolution of each version. Through analysis we found that the complexity of system was increasing with the development and evolution of JDK, leading to a downward trend in its modularity. And after appropriate adjustments for the structure, its modularity show significant upside potential. This indicates that the existing structure of large-scaled software system can also continue to be optimized. |