How to maximize performance and user experience? There are few things that could affect your web app performance and user experience. In my opinion for a better user experience, we should have "Let UI display first, content later". Asynchronously displaying content is the key to boost user experience. Suggestion is to use AngularJS to perform an asynchronous call

Here is my high-level design on my Spring MVC project

View represents your jsp files (html, css, javascript, jquery, and angular js ajax http.post)

Controller represents java files with @Controller and @RequestMapping and if required @RequestParam to accept input parameter from view

Model represents java files for your business object

Service represents java files for your business logic, and have direct access to Helper classes. This is where you set for example wsdl request parameters, and map response from WSDL java object to your POJO Model 

Helper represents java files that have direct access to WSDL to perform service call