Java EE and application servers, part two

From the previous post, we now understand that a Java EE application cannot run except inside a Java EE application server, and that the application server is a Java program that provides functionality and services to Java EE applications. This scenario is illustrated in the following figure:

Java EE application server

The system administrator starts the application server. As an application developer, you will run an application server in your development machine for testing your applications. While you need to learn the basics of running and configuring an application server, you do not need to become an expert on it. You can subscribe to a Java EE service on the cloud and submit your applications to it, as we will see in future posts.

You can deploy several Java EE applications to an application server. Deploying a Java EE application is like installing that application into the application server and activating it so that it can respond to requests from clients. The configuration settings included in each application tell the application server at what URLs the application should be accessible to clients, among other things.