Code Improvement: Implementing Design Patterns to Java EE Applications

Design patterns, acting actually as recurring solutions to common problems, offer significant benefits such as avoiding unnecessary complexity, and promoting code reuse, maintainability and extensibility. This paper describes how four not technology-specific or language-specific design patterns (Front Controller, Model View Controller, Transfer Object and Service to Worker) can be implemented to Java EE applications. It also calculates the code improvement after the implementation of each design pattern using software metrics. The improvement of the quality of the code is considered by measuring the decrease of complexity, coupling or/and response size