Apache TomEE Web Profile delivers Servlets, JSP, JSF, JTA, JPA, CDI, Bean Validation and EJB Lite
Apache TomEE JAX-RS delivers the Web Profile plus JAX-RS
Apache TomEE Plus delivers all that is in the Web Profile and JAX-RS, plus EJB Full, Java EE Connector Architecture, JMS and JAX-WS.
An "EJB" Server that can be run as a separate, standalone, server process. Contains EJB Full, CDI, JPA, JMS, JAX-WS, JAX-RS
A version of Apache OpenEJB that can be dropped into any Tomcat 7.x install effectively creating your own Apache TomEE Web Profile or Apache TomEE Plus.
Should you want to build any of the above binaries, this source bundle is the right one and covers them all.
Currently, we have over 80 examples of various aspects of Java EE 6 ranging from EJB, CDI, JAX-RS and more. If you're learning Java EE, this is your secret weapon.