May you are a bit reserved to start with Java EE, because it looks so confusion. But don't worry it's not so difficult like it seems in the beginning.

As first is important to understand the game of the name. Since Java EE8 the eclipse foundation took the ownership from Oracle maintenance the Java Enterprise Platform. The eclipse foundation and Oracle was not able to find a common agreement for the usage of the Java Trademark. As solution Java EE was renamed to Jakarta EE.

Another fact we need to keep in mind is that Java EE is a collection of specifications. The reference implementation of those specifications is a bundle called application server. If you plan a small project just using the Servlet specification, you don't need to deal with a full application server. A simple Servlet container like Tomcat or Jetty contains everything you need.

Now comes the tricky part. to run a application server or a Servlet container you need a Java Virtual Machine (JVM). The version of the JVM must fit with the specification need of you application server. You need also to check which J EE version is supported by your application server. To stay a bit secure, without updating your environment every 6 months you can use the Java LTS release. Java 11 will have support until 2021 and Java 17 (LTS) released in September 2021 will have for 3 years support until 2024.

If you searching for an compact overview of the Jakarta EE Specification details you can check out my blog post: Java Enterprise in briefly detail

If you like my work, feel free to give a like and share with you friends and / or colleges.