Apache Tomcat is a Java servlet container which implements the following specifications:
- Java Servlet Specification
- Java ServerPages (JSP)
- Expression Language (EL)
- WebSocket
The version of Tomcat you choose will dictate the versions of the above specifications that are supported.
Apache TomEE is a Java EE Web Profile-certified stack which is built on top of an Apache Tomcat base integrated with additional related technologies. It adds implementations for the following specifications (using the Apache project shown in parentheses):
- CDI - Apache OpenWebBeans
- EJB - Apache OpenEJB
- JPA - Apache OpenJPA
- JSF - Apache MyFaces
- JSP - Apache Tomcat
- JSTL - Apache Tomcat
- JTA - Apache Geronimo Transaction
- Servlet - Apache Tomcat
- Javamail - Apache Geronimo JavaMail
- Bean Validation - Apache BVal
Apache TomEE+ adds:
- JAX-RS - Apache CXF
- JAX-WS - Apache CXF
- JMS - Apache ActiveMQ
- Connector - Apache Geronimo Connector
Note that all of this was available from some obvious places on these Apache web sites:
If I understand correctly, the whole EAR thing has been abandoned in favor of good-old WAR files. But, if you have to deploy an EAR file, you are more than likely going to require Apache TomEE. Apache Tomcat certainly doesn't know what the heck to do with an EAR file.