We are used to Node.js / Python / Insert X.
Moving to a Java EE stack, it seems to me like all of the resources are 'press this button', 'do that' without any actual architectural explanation.
For the time being I'm interested in answers to the following questions (I'm completely ignorant on the topic, so some of them may sound stupid):
How does the Rest-API fit into the picture? It seems like EE Servers don't implement them themselves, so one has to use Jenkins. What is it? How does the server understand how to reroute requests to the 'Jenkins classes'
How are these 'Jenkins classes' handled? Does the server create a new thread for each request?