How to deepen your knowledge of Java EE?

Question

Java

I, as a conscientious junior, studied Java Core, then began to study Java Web. Wrote several simple web applications. But since I studied on my own, there are some gaps in knowledge. I know that I can write a website in Java, but I don't fully understand how it works.
How does Tomcat or Jetty work, for example(1).
Why you need to specify artifact in IDE configs and what it is (2).
What is the difference between WAR and WAR exploded(3).
Why web.xml is needed, I know the specific definition, and I understand approximately what it does, but there is no complete understanding at the technical level (4).
In the end, here we define pom.xml, web.xml, java classes in our application, what does our IDE do next to make it all come together and work (5).
What is the difference between a so-called servlet container and a complete server for a java site(6).
I would like to fully understand how and why the site works, and what role each part plays in it.

Recommend some technical literature on the above and related topics.

Answer 1

To get a job. You can normally master JEE only after 3-5 years of work on real projects. It's a paradox, but I haven't seen any good literature on this subject that doesn't involve experience.

Answer 2

In fact, you wrote a whole book of questions here. Just don't answer.
In short,
1) Implement the Servlets API (described in JEE), each in their own way. But in general, they simply process the request and send it to the corresponding (defined in the config) servlet. I propose to study the source code - the code is open.
2) What are IDE configs? As I understand it, the artifact is from Maven? or not?
4) web.xml is the tomcat configuration file. As far as I know other servers define their own files.
6) What do you mean by a full-fledged server for java sites? Give examples.

Answer 3

Hello!
I myself am now studying java EE and the Spring framework at an amateur level.
There are a lot of materials, but to be honest, understanding comes with time. For example, I took a small project for self-development and am working on the implementation in spring. Of course, there are problems and here the literature, the toaster and stackoverflow already help me.