Depending on the amount of customization or development work required, at some point you need to verify your deployment architecture; you need to test the solution against the use cases to verify that you can meet quality-of-service requirements.
If you have relatively few custom-developed services (a mostly out-of-the-box deployment), your solution might simply require customization of Java ES components and a pilot test of the system.
However, if you have developed significant new application logic and created custom services, this testing might be more extensive, involving prototype testing, integration testing, and so forth.
If this testing reveals shortcomings in your deployment architecture, you modify the architecture and test again. This iterative process should eventually result in a deployment architecture and implementation that is ready for deployment in a production environment.