I recommend reading the following.
Transactions:
Chapter 9 of Beginning Java EE 7:
http://find.lib.uts.edu.au/?R=OPAC_b2874770
Security:
The OWASP top-ten:
http://owasptop10.googlecode.com/files/OWASP Top 10 - 2013.pdf
At this point, you should have a good grasp of Java EE. Where you go next is up to you!
Here's a few ideas:
Oracle's Java EE Tutorial
The Java EE Tutorial is quite challenging and much more comprehensive than this course (the PDF is almost 1000 pages).
However, now that you've got a good understanding of most of the platform, you may find the tutorial useful for learning about more obscure aspects of Java EE:
https://docs.oracle.com/javaee/7/tutorial/index.html
Spring Framework
Spring Web MVC is a popular alternative to JavaServer Faces.
At the moment, it has more widespread use.
However, Spring and Java EE are becoming increasingly similar to each other.
There are many new features coming into Java EE 8, including a new MVC framework.
This will bring Spring and Java EE even closer together.
https://spring.io/
Spring support is built into NetBeans, so you can easily experiment with it.
Just create a new "Web Application" (in the "Java Web" category) and at the last step, select Spring Web MVC instead of JavaServer Faces.
Just Start Coding...
To become even more expert at Java EE, my best suggestion is to just start coding.
Dream up an application and start programming.
If you're not sure about something, then refer to the tutorials.
Also remember that the specifications are often quite readable.
If you want the definitive answer, you can always search the specifications:
http://www.oracle.com/technetwork/java/javaee/tech/index.html