In recent past every discipline and every industry have their own methods of developing products. It may
be software development, mechanics, construction, psychology and so on. These demarcations work fine
as long as the requirements are within one discipline. However, if the project extends over several
disciplines, interfaces have to be created and coordinated between the methods of these disciplines.
Performance is an important quality aspect of Web Services because of their distributed nature.
Predicting the performance of web services during early stages of software development is significant. In
Industry, Prototype of these applications is developed during analysis phase of Software Development Life
Cycle (SDLC). However, Performance models are generated from UML models. Methodologies for
predicting the performance from UML models is available. Hence, In this paper, a methodology for
developing Use Case model and Activity model from User Interface is presented. The methodology is
illustrated with a case study on Amazon.com