Saturday, August 16, 2008

How to implement EJB 3.0 <env-entry/> in ejb-jar.xml

A topic which is mentioned in the EJB 3.0 Specification (JSR-220) is the ability to add environment entries in ejb-jar.xml file. What I found interesting is that I could not Google for a good example of how to implement it. As a result, I thought I would provide a good simple example.

The first item you should examine is the schema resources for Java EE. Specifically we want to examine the ejb-jar_3_0.xsd. This file contains all of the information we need to create and validate an ejb-jar.xml file.

First we create an ejb-jar.xml file in our EJB project. This file should contain the following information at a minimum:

1 <?xml version="1.0" encoding="UTF-8"?>
2 <ejb-jar
3 xmlns=""
4 xmlns:xsi=""
5 xsi:schemaLocation="
7 version="3.0">
8 </ejb-jar>

From here we can add our beans and environment variables. I have created an example project which demonstrates how to use the environment variables. Here is my ejb-jar file:

1 <?xml version="1.0" encoding="UTF-8"?>
2 <ejb-jar
3 xmlns=""
4 xmlns:xsi=""
5 xsi:schemaLocation="
7 version="3.0">
8 <enterprise-beans>
9 <session>
10 <ejb-name>EnvironmentalResourceInjectionExampleBean</ejb-name>
11 <env-entry>
12 <env-entry-name>s1</env-entry-name>
13 <env-entry-type>java.lang.String</env-entry-type>
14 <env-entry-value>Hello</env-entry-value>
15 </env-entry>
16 <env-entry>
17 <env-entry-name>s2</env-entry-name>
18 <env-entry-type>java.lang.String</env-entry-type>
19 <env-entry-value>EJB Resource Injection World!</env-entry-value>
20 </env-entry>
21 </session>
22 </enterprise-beans>
23 </ejb-jar>
In my example, I use a stateless session bean with @WebService annotation. This allows me to test it right in GlassFish. I also use the @Resource annotation to inject my environment entries. I have used the name attribute to give it a JNDI lookup value. This works for GlassFish. Other containers may use the mappedName attribute.

Here is my stateless session bean:

1 /*
2 *
3 * Blue Lotus Software, LLC
4 *
5 * $Id: 100 2008-08-16 21:57:19Z jyeary $
6 *
7 * Copyright [2008] [John Yeary]
8 * Licensed under the Apache License, Version 2.0 (the "License");
9 * you may not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package;
20 import javax.annotation.Resource;
21 import javax.ejb.Stateless;
22 import javax.jws.WebMethod;
23 import javax.jws.WebService;
25 /**
26 *
27 * @author John Yeary
28 * @version 1.0
29 */
30 @Stateless
31 @WebService
32 public class EnvironmentalResourceInjectionExampleBean implements
33 EnvironmentalResourceInjectionExampleRemote,
34 EnvironmentalResourceInjectionExampleLocal {
36 @Resource(name = "s1")
37 String s1;
38 @Resource(name = "s2")
39 String s2;
41 public String printEnv() {
42 return s1 + " " + s2;
43 }
45 @WebMethod
46 public String printEnvironment() {
47 return printEnv();
48 }
49 }

When I deploy the application to GlassFish, I can use the Web Service Tester to validate that I get the injected values.

As we can see, the values s1 and s2 are sucessfully injected. The complete Netbeans 6.1 project and source can be found here.


Matti said...


thanks for this good example. One question still remains, at least for me. Is it possible to modify values of these env variables after deployment?
Eg by Glassfish admin console or by Glassfish asadmin command line tool?

regards, Matti

chanura hemal said...

i tried a example with env-entry in ejb 3 with relaven xmlns. but always i got

Caused by: org.jboss.xb.binding.JBossXBException: Failed to parse source: cvc-complex-type.2.4.a: Invalid content was fo
und starting with element 'env-entry'. One of '{"":ejb-local-ref, "
xml/ns/javaee":service-ref, "":resource-ref, "":resour
ce-env-ref, "":message-destination-ref, "":persistence
-context-ref, "":persistence-unit-ref, "":post-constru
ct, "":pre-destroy, "":post-activate, "http://java.sun
.com/xml/ns/javaee":pre-passivate, "":security-role-ref, "
vaee":security-identity}' is expected. @ vfszip:/C:/WORK_SPACE/MyJboss5/jboss-5.1.0.GA/server/default/deploy/Jboss5App1.

error. i am using

ejb-jar xmlns = ""
version = "3.0"
xmlns:xsi = ""
xsi:schemaLocation = "" tag for ejb-jar.xml.

please give a advice to solve this.thanks

chanrua hemal

John Yeary said...

The error message indicates that you do not have the correct elements in your xml file. I would look at the reference to make sure you are using the correct elements. NetBeans gives you hints at adding elements.

John Yeary said...

If you look in the ejb-jar_3_0.xsd, it gives you an exact blueprint on creating your own ejb-jar.xml file.

傻傻豪 said...

hi, chanura hemal, i got same problem with you.
when i checked xsd file, it is valid for me, but why jboss error again. Again i found that, the resource-ref element I put in front of env-entry element, so that it go error, while you put that in different order, it go normal again.

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