EJB

This section describes how to add support of EJB in Apache Karaf. It doesn’t describe how to develop EJB applications.

Apache OpenEJB

Apache Karaf doesn’t provide "native" support of EJB (Enterprise Java Beans).

Apache OpenEJB provides EJB support for Apache Karaf by providing a set of features.

You have to update some Karaf configuration to have full OpenEJB support.

First, in the etc/system.properties, you have to append the following properties:

...
#
# OpenEJB scanner
#
openejb.deployments.classpath.exclude=bundle:*
openejb.deployments.classpath.filter.descriptors=true

Due to some OpenEJB version constraints, you also have to update the etc/jre.properties by changing the version of the javax.xml.namespace package, and remove the version of the javax.annotation package (provided by Geronimo Annotation API spec bundle, used by OpenEJB):

...
javax.annotation, \
javax.annotation.processing, \
...
javax.xml.namespace;version="1.0.0", \
...

It enables the OpenEJB bundles scanning, looking for EJBs.

After starting/restart Karaf to take these changes, we can install the OpenEJB feature:

karaf@root()> feature:repo-add openejb

By default, the feature:repo-add openejb command will install the latest OpenEJB version available.

You can specify a target version using the version argument:

karaf@root()> feature:repo-add openejb 4.5.2

Now, you have a set of new OpenEJB features available in your Apache Karaf container:

karaf@root()> la
...
openejb-core                  | 4.5.2 |           | openejb-features          |
openejb-server                | 4.5.2 |           | openejb-features          |
openejb-cxf                   | 4.5.2 |           | openejb-features          |
openejb-rest                  | 4.5.2 |           | openejb-features          |
openejb-soap                  | 4.5.2 |           | openejb-features          |

You can add EJB support installing the openejb-core feature:

karaf@root()> feature:install openejb-core

Apache KarafEE

A custom distribution of Apache Karaf embedding OpenEJB is available in the Apache TomEE project.

The name of this custom distribution is KarafEE: https://svn.apache.org/repos/asf/tomee/karafee/

However, this project is now "deprecated", and all resources from KarafEE will move directly to Apache Karaf soon.