:index-group: General Information
:jbake-date: 2018-12-05
:jbake-type: page
:jbake-status: published


NOTE: Licensed to the Apache Software Foundation (ASF) under
one or more contributor license agreements. See the NOTICE file
distributed with this work for additional information regarding
copyright ownership. The ASF licenses this file to you under the Apache
License, Version 2.0 (the "License"); you may not use this file except
in compliance with the License. You may obtain a copy of the License at
. http://www.apache.org/licenses/LICENSE-2.0 . Unless required by
applicable law or agreed to in writing, software distributed under the
License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied. See the License for
the specific language governing permissions and limitations under the
License.

= Deploying in TomEE

Deploying applications in TomEE is as simple as deploying them in
Tomcat.

You could deploy your application in Eclipse just like how you would
deploy with Tomcat. For an example,
link:tomee-and-eclipse.html[tomee-and-eclipse] shows how to use TomEE
with Eclipse.

Or you can simply package your application as a standard *WAR* file and
copy it to the *[TomEE]/webapps* folder, or as an *EAR* file and copy it
to the *[TomEE]/apps* folder.

Read on to learn more about packaging EJBs in a WAR file.

== Packaging

=== One archive

The basic idea of this approach is that your Servlets and EJBs are
together in your WAR file as one application.

* No classloader boundaries between Servlets and EJBs
* EJBs and Servlets can share all third-party libraries (like Spring!)
* No EAR required.
* Can put the `web.xml` and `ejb-jar.xml` in the same archive (the WAR file)
* EJBs can see Servlet classes and vice versa

=== Not quite J2EE (But it is Java EE 6)

This is very different from J2EE or Java EE 5 as there are not several
levels of separation and classloader hierarchy any more. +
This may take some time getting used to, and it is important to understand
that this style of packaging is *not* J2EE compliant. +
You should not worry though, as it is an accepted feature of Java EE 6.

=== J2EE classloading rules:

* You cannot ever have EJBs and Servlets in the same classloader.
* Three classloader minimum; a classloader for the ear, one for each
ejb-jar, and one for each WAR file.
* Servlets can see EJBs, but EJBs cannot see Servlets.

To pull that off, J2EE has to kill you on packaging: - You cannot have
EJB classes and Servlet classes in the same archive.

* You need at least three archives to combine Servlets and EJBs; 1 EAR
containing 1 EJB jar and 1 Servlet WAR.
* Shared libraries must go in the EAR and be included in a specially
formatted 'Class-Path' entry in the EAR's MANIFEST file.

Critically speaking, forcing more than one classloader on an application
is where J2EE "jumps the shark" for a large majority of people's needs.
