Initially, the complex E-Scan system was based on J2EE, including EJB2. When we took the project over from its former developer, we quickly learned that to be able to further develop it and add the functions the client was expecting us to implement we would have to migrate it. We therefore decided to migrate the app step by step to the newest Java technology.
The platform had to be available for its users while it was being improved. The customers who paid for the access were using the tool on a daily basis so it had to remain up and running. We already had a great deal of experience in managing projects like this, we were able to ensure the customers wouldn’t notice that some works were conducted. They could perform the surveys without any interruptions.
The database model used in the app was complicated, so we decided to leave the application layer as is and rewrite the business logic and the presentation layers. Currently, the product is based on the Spring framework. The database communication layer was developed with JPA and the UI – with Spring MVC/JSP/JSTL/Tiles/JQuery/Spring Security. The network service layer is also Spring-based. JMS was used for the asynchronous queuing and e-mail sending purposes. We use Maven tools to manage the project and Eclipse IDE to develop the app.