With SaaS application, tenant can focus on application utilization while Independent Software Vendor (ISV) is responsible for application dep- loyment, installation, operation and maintenance. Using Aspect Oriented Soft- ware Development (AOSD), we propose eight concerns, i.e. configurability, discriminator, measurement, monitoring, tenant management, billing manage- ment, performance management, and application management. Those concerns are integrated into a SaaS system architectural design, to enhance SaaS opera- tional flexibility and maintainability. As a proof of concept, we developed a SaaS operational environment using Spring and AOP. Two Java applications have been integrated to this environment after tailoring. We have tested the modules, classes and services and then the applications, to demonstrate that the platform is able to run a set of web applications as a SaaS. Using this system, ISV can modify an existing Java application easily to be a part of SaaS and measure resource usage and monitor SaaS operation by a dashboard.