About Dependency Injection in EJB3.0

Hi,
I'm a fresh man in EJB3.0.
Except @EJB and @Resource,is there
any other anotation can be used to
Dependency Injection?

There is currently no possiblity in Weblogic 10 server web layer to use Dependency Injection on any other component than the ones defined in web.xml s.a.:
- servlets
- listeners
- filters
See here:
http://e-docs.bea.com/wls/docs100/webapp/annotateservlet.html
A simple POJO class part of the web application (such as a Backing Bean in JSF or an Action in Struts for example) is not benefiting from DI.
Doesn't this make Weblogic 10 a NON JEE 5 compliant server?
Why was this restriction imposed?
And how is one supposed to use DI with a simple POJO class? Why this huge inconvenience?

Similar Messages

Dependency inject a EJB 2.x bean with EJB3

Hi there
I have an old EJB3 2.x bean deployed on my server, that is registered in JNDI with the name "abc/xyz/ItemLookup_v35".
Now I wrote a EJB3 SFSB bean and I want to access the old bean using dependency injection. I tried it with the annotation
@EJB(mappedName = "abc/xyz/ItemLookup_v35")
private ItemLookupRemote itemRemote;but it wasn't working. How can I explicitly set the JNDI name of an old bean, that I want to lookup for?
Any help is appreciated!
Regards,
Stephan
Edited by: MasterRefactorer on Jun 27, 2008 7:31 AM

You can use @EJB to access 2.x Remote views, but the field type has to be the Home interface.
@EJB(mappedName = "abc/xyz/ItemLookup_v35")
private ItemLookupHome itemHome;

Dependency Injection Problem in EJB 3.0

Hello.
I've been trying to get an example of java dependency injection working in JBoss 4.0.5.GA. I've installed it with EJB 3.0 support.
The problem is that if I try to use the injected resource, I get a null pointer exception.
The example I'm trying is a very short and simple one. Shouldn't be hard to figure out what is going wrong. Here it goes:
[root]\src\hello\MessageServlet.java:
package hello;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.List;
import java.util.ListIterator;
import javax.naming.InitialContext;
import javax.annotation.*;
public class MessageServlet extends HttpServlet {
     @Resource (mappedName="java:/DefaultDS")
     javax.sql.DataSource ejb30DB;
     public void init () throws ServletException {
     public void service(HttpServletRequest request, HttpServletResponse response)
               throws IOException, ServletException {
          boolean injectedLookingGood = false;
          boolean notInjectedLookingGood = false;
          try {
               java.sql.Connection conn = ejb30DB.getConnection();
               conn.close();
               injectedLookingGood = true;
          } catch(Exception e) {
               e.printStackTrace();
          try {
               InitialContext ic = new InitialContext();
               javax.sql.DataSource ds = (javax.sql.DataSource)ic.lookup("java:/DefaultDS");
               java.sql.Connection conn = ds.getConnection();
               conn.close();
               notInjectedLookingGood = true;
          } catch(Exception e) {
               e.printStackTrace();
          response.setContentType("text/html");
          ServletOutputStream out = response.getOutputStream();
          out.println("<html>");
          out.println("<head><title>Hello World</title></head>");
          out.println("<body>");
          out.println("<h1>Hello World</h1>");
          out.println("<form action=\"HelloWorld\" method=\"get\">");
          out.print("Injected DataSource is looking ");
          if(injectedLookingGood) {
               out.println("good <br>");
          else {
               out.println("bad <br>");
          out.print("Not-Injected DataSource is looking ");
          if(notInjectedLookingGood) {
               out.println("good <br/>");
          else {
               out.println("bad <br/>");
          out.println("<input type=\"submit\" value=\"Test Some More\">");
          out.println("</form>");
          out.println("</body>");
          out.println("</html>");
[root]\etc\META-INF\web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
<display-name>HelloWorldWAR</display-name>
<servlet>
<display-name>HelloWorld</display-name>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>hello.MessageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldServlet</servlet-name>
<url-pattern>/servlet/HelloWorld</url-pattern>
</servlet-mapping>
</web-app>
[root]\etc\META-INF\application.xml:
<?xml version="1.0" encoding="UTF-8"?>
<application xmlns="http://java.sun.com/xml/ns/j2ee" version="1.4"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com /xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/application_1_4.xsd">
<display-name>HelloWorld</display-name>
<description>Application description</description>
<module>
<web>
<web-uri>web-ejb3.war</web-uri>
<context-root>HelloWorld</context-root>
</web>
</module>
</application>
[root]\build.xml:
<project name="HelloWorld" default="all" basedir=".">

<property name="proj.name" value="HelloWorld"/>
<property name="proj.version" value="1.0"/>

<property name="src.dir" value="${basedir}/src"/>
<property name="build.dir" value="${basedir}/bin"/>
<property name="lib.dir" value="${basedir}/lib"/>
<property name="build.classes.dir" value="${build.dir}/classes"/>
<property name="build.jar.dir" value="${build.dir}/jar"/>
<property name="src.etc.dir" value="${basedir}/etc"/>
<property name="meta-inf.dir" value="${src.etc.dir}/META-INF"/>

<path id="build.classpath">
<fileset dir="${lib.dir}">
<include name="**/*.jar"/>
<include name="**/*.zip"/>
</fileset>
</path>

<patternset id="meta.files">
<include name="**/*.xml" />
<include name="**/*.properties"/>
</patternset>
<target name="prepare">
<mkdir dir="${build.dir}"/>
<mkdir dir="${build.classes.dir}"/>
<mkdir dir="${build.jar.dir}"/>
</target>
<target name="compile" depends="prepare">
<javac destdir="${build.classes.dir}"
classpathref="build.classpath"
debug="on">
<src path="${src.dir}"/>
</javac>
</target>
<target name="package-web" depends="compile">
<war warfile="${build.dir}/jar/web-ejb3.war"
webxml="${meta-inf.dir}/web.xml">
<classes dir="${build.dir}/classes">
<include name="**/*Servlet.class"/>
</classes>
</war>
</target>

<target name="assemble-app">
<ear destfile="${build.jar.dir}/HelloWorld.ear" appxml="${meta-inf.dir}/application.xml">
<fileset dir="${build.dir}/jar"
includes="*.war"/>
</ear>
</target>
<target name="clean">
<delete dir="${build.dir}" />
</target>
<target name="all">
<antcall target="clean" />
<antcall target="package-web" />
<antcall target="assemble-app" />
</target>
</project>
Any help would be apreciated.
Thanks in advance,
Hugo Oliveira
[email protected]

Hello Ken.
I gess dependency injection is unnavailable in servlets as of this moment. I conducted another test using a session bean that injects and tests the DataSource and a servlet calling the session bean via a refference obtained from InitialContext. It worked OK.
Here's the code:
[root]/src/hello/MessageHandler.java:
package hello;
public interface MessageHandler {
     public boolean testInjection();
[root]/src/hello/MessageHandlerBean.java:
package hello;
import javax.ejb.Stateless;
import javax.persistence.*;
import java.util.List;
import javax.annotation.*;
@Stateless
public class MessageHandlerBean implements MessageHandler {
     @Resource (mappedName="java:/DefaultDS")
     private javax.sql.DataSource ds;
     public boolean testInjection() {
          try {
               java.sql.Connection conn = ds.getConnection();
               conn.close();
               return true;
          } catch(Exception e) {
               e.printStackTrace();
          return false;
[root]/src/hello/MessageServlet.java:
package hello;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.List;
import java.util.ListIterator;
import javax.naming.InitialContext;
import javax.annotation.*;
public class MessageServlet extends HttpServlet {
     public void init () throws ServletException {
     public void service(HttpServletRequest request, HttpServletResponse response)
               throws IOException, ServletException {
          boolean injectedLookingGood = false;
          try {
               InitialContext ic = new InitialContext();
               MessageHandler mh = (MessageHandler)ic.lookup("HelloWorld/MessageHandlerBean/local");
               injectedLookingGood = mh.testInjection();
          } catch(Exception e) {
               e.printStackTrace();
          response.setContentType("text/html");
          ServletOutputStream out = response.getOutputStream();
          out.println("<html>");
          out.println("<head><title>Hello World</title></head>");
          out.println("<body>");
          out.println("<h1>Hello World</h1>");
          out.println("<form action=\"HelloWorld\" method=\"get\">");
          out.print("Injected DataSource is looking ");
          if(injectedLookingGood) {
               out.println("good <br>");
          else {
               out.println("bad <br>");
          out.println("<input type=\"submit\" value=\"Test Some More\">");
          out.println("</form>");
          out.println("</body>");
          out.println("</html>");
[root]/etc/META-INF/application.xml:
<?xml version="1.0" encoding="UTF-8"?>
<application xmlns="http://java.sun.com/xml/ns/j2ee" version="1.4"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com /xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/application_1_4.xsd">
<display-name>HelloWorld</display-name>
<description>Application description</description>
<module>
<ejb>HelloWorld.ejb3</ejb>
</module>
<module>
<web>
<web-uri>web-ejb3.war</web-uri>
<context-root>HelloWorld</context-root>
</web>
</module>
</application>
[root]/etc/META-INF/web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name>HelloWorldWAR</display-name>
<servlet>
<display-name>HelloWorld</display-name>
<servlet-name>HelloWorldServlet</servlet-name>
<servlet-class>hello.MessageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorldServlet</servlet-name>
<url-pattern>/servlet/HelloWorld</url-pattern>
</servlet-mapping>
</web-app>
[root]/build.xml:
<project name="HelloWorld" default="all" basedir=".">

<property name="proj.name" value="HelloWorld"/>
<property name="proj.version" value="1.0"/>

<property name="src.dir" value="${basedir}/src"/>
<property name="build.dir" value="${basedir}/bin"/>
<property name="lib.dir" value="${basedir}/lib"/>
<property name="build.classes.dir" value="${build.dir}/classes"/>
<property name="build.jar.dir" value="${build.dir}/jar"/>
<property name="src.etc.dir" value="${basedir}/etc"/>
<property name="meta-inf.dir" value="${src.etc.dir}/META-INF"/>

<path id="build.classpath">
<fileset dir="${lib.dir}">
<include name="**/*.jar"/>
<include name="**/*.zip"/>
</fileset>
</path>

<patternset id="meta.files">
<include name="**/*.xml" />
<include name="**/*.properties"/>
</patternset>
<target name="prepare">
<mkdir dir="${build.dir}"/>
<mkdir dir="${build.classes.dir}"/>
<mkdir dir="${build.jar.dir}"/>
</target>
<target name="compile" depends="prepare">
<javac destdir="${build.classes.dir}"
classpathref="build.classpath"
debug="on">
<src path="${src.dir}"/>
</javac>
</target>
<target name="package-ejb" depends="compile">
<jar jarfile="${build.jar.dir}/HelloWorld.ejb3">
<fileset dir="${build.classes.dir}">
<include name="**/*.class"/>
</fileset>

</jar>
</target>
<target name="package-web" depends="compile">
<war warfile="${build.dir}/jar/web-ejb3.war"
webxml="${meta-inf.dir}/web.xml">


<classes dir="${build.dir}/classes">
<include name="**/*Servlet.class"/>
</classes>
</war>
</target>

<target name="assemble-app">
<ear destfile="${build.jar.dir}/HelloWorld.ear" appxml="${meta-inf.dir}/application.xml">
<fileset dir="${build.dir}/jar"
includes="*.ejb3,*.war"/>
</ear>

</target>
<target name="clean">
<delete dir="${build.dir}" />
</target>
<target name="all">
<antcall target="clean" />
<antcall target="package-ejb" />
<antcall target="package-web" />
<antcall target="assemble-app" />
</target>
</project>
Thanks,
Hugo Oliveira
[email protected]

EJB 3.0 Dependency Injection in JSF ?

Hi,
I have a question about ejb 3.0 dependency injection in a JSF WebApp:
I Build successfully a Web Module (version 2.5) an EJB Module (version 3.0) and an EAR Module (Version 5.0). The EAR App can be deployed without errors on a Bea WebLogic Server 10.1. All modules are successfully deployed.
Inside the Web Module there is a Servlet which uses dependency injection to access the session EJB form the EJB Module. This works perfect.
Next I try to use the same EJB with dependency injection from the JSF Page via a backing bean. But when I try to access my JSP Page I got a Nullpointer Exception.
It seems that the Dependency Injection in the JSP App did not work?
Can anybody give me a hint what could be wrong?
Thanks
Ralph

There is currently no possiblity in Weblogic 10 server web layer to use Dependency Injection on any other component than the ones defined in web.xml s.a.:
- servlets
- listeners
- filters
See here:
http://e-docs.bea.com/wls/docs100/webapp/annotateservlet.html
A simple POJO class part of the web application (such as a Backing Bean in JSF or an Action in Struts for example) is not benefiting from DI.
Doesn't this make Weblogic 10 a NON JEE 5 compliant server?
Why was this restriction imposed?
And how is one supposed to use DI with a simple POJO class? Why this huge inconvenience?

Types of dependency injection.

Hi,
I wanted to know some details about difference between setter and constructor based dependency injection(IOC)
I didnt understood the foll things :
1. "setter based IOC is good for object that take optional parameters and objects that need to change their parameters many times during their lifecycles." The object which is referred is the object to be injected ?
2. In the Constructor based IOC "the creater knows about the referenced object".
Providing links or giving simple examples would be appreciated.
Thanks in advance.

Hi,
I wanted to know some details about difference
between setter and constructor based dependency
injection(IOC)
I didnt understood the foll things :
1. "setter based IOC is good for object that take
optional parameters and objects that need to change
their parameters many times during their lifecycles."
The object which is referred is the object to be
be injected ?Yes, what else would make sense?
2. In the Constructor based IOC "the creater knows
about the referenced object". Because the referenced object is a parameter in the constructor call.
Providing links or giving simple examples would be appreciated.Martin Fowler's IoC article is the best explanation I've ever read:
http://www.martinfowler.com/articles/injection.html
%

Design Issue: Localization using Lookup OR Dependency Injection

Hello Forums!
I'm having a design issue regarding localization in my application. I'm using Spring Framework (www.springframework.org) as an
application container, which provides DI (dependency injection) - but the issue is not Spring- but rather design related. All localization
logic is encapsulated in a separate class ("I18nManager"), which basically is just a wrapper around multiple Java ResourceBundles.
Right now localization is performed in the "traditional" look-up style, e.g.
ApplicationContext.getMessage("some.message.key");
where ApplicationContext is a wrapper around the Spring application context and getMessage(...) is a static method on that
context. The advantage of that solution is a clean & simple interface design, localization merely becomes a feature of classes, but
is not part of their public API. The only problem with that approach is the very tight coupling of Classes to the ApplicationContext, which
really is a problem when you want to use code outside of an application context. The importance of this problem increases if one considers
that I18N is a concern that can be found in every application layer, from GUI to business to data tier, all those components suddenly depdend
on an application context being present.
My proposed solution to this problem is a "Localizable" interface, which may provide mutators for an "I18NManager" instance that can be
passed in. But is this really a well-designed solution, as almost any object in an application may be required to implement this interface?
I'm too concerned about performance: the look-up solution does not need to pass references to localizable objects, whereas my proposed solution
will require 1 I18NManager reference per localizable object, which might cause troubles if you let's say load 10.000 POJOs from some database that
are all localizable.
So (finally) my question: how do you handle such design issues? Are there any other solutions out there that I'm not aware of yet? Comments/Help welcome!

michael_schmid wrote:
Hello Forums!
I'm having a design issue regarding localization in my application. I'm using Spring Framework (www.springframework.org) as an
application container, which provides DI (dependency injection) - but the issue is not Spring- but rather design related. All localization
logic is encapsulated in a separate class ("I18nManager"), which basically is just a wrapper around multiple Java ResourceBundles.Why do you think you need a wrapper around resource bundles? Spring does very well with I18N, as well as Java does. What improvement do you think you bring?
Right now localization is performed in the "traditional" look-up style, e.g.
ApplicationContext.getMessage("some.message.key");
where ApplicationContext is a wrapper around the Spring application context and getMessage(...) is a static method on that
context. Now you're wrapping the Spring app context? Oh, brother. Sounds mad to me.
The advantage of that solution is a clean & simple interface design, localization merely becomes a feature of classes, but
is not part of their public API. The only problem with that approach is the very tight coupling of Classes to the ApplicationContext, which
really is a problem when you want to use code outside of an application context. The importance of this problem increases if one considers
that I18N is a concern that can be found in every application layer, from GUI to business to data tier, all those components suddenly depdend
on an application context being present.One man's "tight coupling" is another person's dependency.
I agree that overly tight coupling can be a problem, but sometimes a dependency just can't be helped. They aren't all bad. The only class with no dependencies calls no one and is called by no one. We'd call that a big, fat main class. What good is that?
Personally, I would discourage you from wrapping Spring too much. I doubt that you're improving your life. Better to use Spring straight, the way it was intended. I find that they're much better designers than I am.
My proposed solution to this problem is a "Localizable" interface, which may provide mutators for an "I18NManager" instance that can be
passed in. But is this really a well-designed solution, as almost any object in an application may be required to implement this interface?I would say no.
I'm too concerned about performance: the look-up solution does not need to pass references to localizable objects, whereas my proposed solution
will require 1 I18NManager reference per localizable object, which might cause troubles if you let's say load 10.000 POJOs from some database that
are all localizable.
So (finally) my question: how do you handle such design issues? Are there any other solutions out there that I'm not aware of yet? Comments/Help welcome!I would use the features that are built into Spring and Java until I ran into a problem. It seems to me that you're wrapping your way into a problem and making things more complex than they need to be.
%

Dependency injection nightmare

I can't get it what is wrong...given this faces-config.xml
<faces-config xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd"
     version="1.2">
     <application>
          <view-handler>com.icesoft.faces.facelets.D2DFaceletViewHandler</view-handler>
     </application>
     <managed-bean>
          <managed-bean-name>persistenceManager</managed-bean-name>
          <managed-bean-class>ro.sinoptix.controller.PersistenceManager</managed-bean-class>
          <managed-bean-scope>application</managed-bean-scope>
     </managed-bean>
     <managed-bean>
          <managed-bean-name>tipCerereCtrl</managed-bean-name>
          <managed-bean-class>ro.sinoptix.controller.TipCerereCtrl</managed-bean-class>
          <managed-bean-scope>session</managed-bean-scope>
          <managed-property>
               <property-name>persistenceManager</property-name>
               <property-class>ro.sinoptix.controller.PersistenceManager</property-class>
               <value>#{persistenceManager}</value>
          </managed-property>
     </managed-bean>
     <managed-bean>
          <description>tine pagina TipuriCerere</description>
          <managed-bean-name>tipuriCerere</managed-bean-name>
          <managed-bean-class>ro.sinoptix.view.TipuriCerere</managed-bean-class>
          <managed-bean-scope>request</managed-bean-scope>
          <managed-property>
               <property-name>tcl</property-name>
               <property-class>ro.sinoptix.controller.TipCerereCtrl</property-class>
               <value>#{tipCerereCtrl}</value>
          </managed-property>
     </managed-bean>
</faces-config>i get this error
SEVERE: JSF1054: (Phase ID: RENDER_RESPONSE 6, View ID: /TipuriCerere.xhtml) Exception thrown during phase execution: javax.faces.event.PhaseEvent[source=com.sun.faces.lifecycle.LifecycleImpl@7a36a2]
SEVERE: Exception occured during rendering on http://localhost:8080/SOConfigManager/TipuriCerere.jsf [/TipuriCerere.xhtml]
javax.faces.FacesException: Problem in renderResponse: com.sun.faces.mgbean.ManagedBeanPreProcessingException: Unexpected error processing managed bean tipuriCerere
Caused by: com.sun.faces.mgbean.ManagedBeanPreProcessingException: Unexpected error processing managed bean tipuriCerere
     at com.sun.faces.mgbean.BeanManager.preProcessBean(BeanManager.java:356)
     at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:201)
     at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:86)
     at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54)
     at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72)
     at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:61)
     at org.apache.el.parser.AstValue.getValue(AstValue.java:107)
     at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
     at com.sun.facelets.el.TagValueExpression.getValue(TagValueExpression.java:71)
     at javax.faces.component.UIData.getValue(UIData.java:609)
     at com.icesoft.faces.component.panelseries.UISeries.getValue(UISeries.java:572)
     ... 65 more
Caused by: com.sun.faces.mgbean.ManagedBeanPreProcessingException: Unexpected error processing managed property tcl
     at com.sun.faces.mgbean.ManagedBeanBuilder.bake(ManagedBeanBuilder.java:117)
     at com.sun.faces.mgbean.BeanManager.preProcessBean(BeanManager.java:311)
     ... 75 more
Caused by: java.lang.NullPointerException
     at com.sun.faces.mgbean.ManagedBeanBuilder.bakeBeanProperty(ManagedBeanBuilder.java:350)
     at com.sun.faces.mgbean.ManagedBeanBuilder.bake(ManagedBeanBuilder.java:107)
     ... 76 morei cant figure out what is wrong ... my classes are
public class TipuriCerere {
     // dependency injection
     private TipCerereCtrl tcl;
        public TipCerereCtrl getTcl() {
          return tcl;
public class TipCerereCtrl {
     private PersistenceManager persistenceManager;
     public PersistenceManager getPersistenceManager() {
          return persistenceManager;
}Any help is valueble to me
Edited by: kquizak on Jan 8, 2010 1:54 AM

r035198x wrote:
gimbal2 wrote:
.... Anybody else have an opinion about this?Definitely odd. Would have expected something like property not accessible.
What JSF implementation and version is this?I just had this happen to me as well today. Added a ManagedProperty to a ViewScoped bean, like so:
     @ManagedProperty(value="#{actionStateMachine}")
     private ActionStateMachine     actionStateMachine;.. and only provided a getter, no setter, ... and I got the same exception shown by the OP.
After I added a setter, the exception does not happen.
Environment:
JBoss 7.1.1
Mojarra 2.1.7-jbossorg-1 (20120227-1401)

Dependency injection across enterprise applications is possible?

Hi All ,
I am working on EJB3.0. I want to know if we can use dependency injection across application?
I have
1. jpadc having all JPA classes and 1 jpaAppl enterprise application having only jpadc
2. session1dc and session1Appl enterprise application for session1dc
3. session2dc and session2Appl enterprise application for session2dc
I want to use jpa classes and sesisonbean classes from jpadc and session2dc respectively
inside session2dc. is it possible? i tried but i am not able to d odependency injection
Please let me know if this is possible?
Thnx in advance
Regards
Kavita

Hi Kavita,
Yes, you can use dependency injection. For more information, refer to this document:
http://help.sap.com/saphelp_nwce711/helpdata/en/44/bf6e9344751eaae10000000a1553f6/frameset.htm
If you need information related to the JPA part, read this:
http://help.sap.com/saphelp_nwce711/helpdata/en/46/307a2a50094f09e10000000a114a6b/frameset.htm
Best regards,
Ekaterina

Dependency injection/annotation Error

Greetings,
Hello everybody !
This topic's about a problem I'm currently experiencing while trying to deploy a Web Application that makes a call to an EJB using Dependency injection from a Servlet. This is the Stack trace generated when I attempt to deploy my web app:
DeployerRunnable.run Error parsing annotation for class org.servlet.TestServletoracle.oc4j.admin.internal.DeployerException: Error parsing annotation for class org.servlet.TestServlet
at oracle.oc4j.admin.internal.DeployerBase.execute(DeployerBase.java:126)
at oracle.oc4j.admin.jmx.server.mbeans.deploy.OC4JDeployerRunnable.doRun(OC4JDeployerRunnable.java:52)
at oracle.oc4j.admin.jmx.server.mbeans.deploy.DeployerRunnable.run(DeployerRunnable.java:81)
at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:303)
at java.lang.Thread.run(Thread.java:619)
Here's a Snippet from the Servlet that's making the call:
*public class TestServlet extends HttpServlet {*
     *@EJB(beanName="MathEjbBean")*
     private org.logic.MathEjbBeanRemote ejb;
     protected void doGet(HttpServletRequest request,
               *HttpServletResponse response) throws ServletException, IOException {*
          ejb.sum(1, 2);
Here's the EJB implementation:
*@Stateless*
*@StatelessDeployment*
*public class MathEjbBean implements MathEjbBeanRemote, MathEjbBeanLocal {*
     *@Override*
     *public int sum(int a, int b) {*
          *// TODO Auto-generated method stub*
          return a + b;
Finally, I will post the Container-specific Deployment descriptor:
<?xml version="1.0" encoding="utf-8"?>
<orion-ejb-jar xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlns.oracle.com/oracleas/schema/orion-ejb-jar-10_0.xsd" deployment-version="" deployment-time="128f9bdc917" schema-major-version="10" schema-minor-version="0" >
<enterprise-beans>
<session-deployment name="MathEjbBean" tx-retry-wait="60" location="MathEjbBean" local-location="MathEJB_MathEjbBeanLocal" persistence-filename="MathEjbBean">
</session-deployment>
</enterprise-beans>
<assembly-descriptor>
<default-method-access>
<security-role-mapping name="<default-ejb-caller-role>" impliesAll="true" />
</default-method-access>
</assembly-descriptor>
</orion-ejb-jar>
Up until this moment, I still have no clue, about the reason why I can't inject my EJB in the Web-app's Servlet.
Please Help Me
It's so hard to find information about this problem on the internet.
Best Regards,
Jose.

Hello there !
I've corrected this problem by using the same name for the @Stateless annotation and the display-name tag in the ejb-jar file, for @EJB this name should match also.
Good Luck, hope this is helpful in the future.

When to use @Resource and when to use @EJB for dependency injection

Hi,
When do you use
@Resource and when do you use @EJB for dependency injection?
Thanks

Captain obvious: Use @EJB for injection of EJBs, and @Resource for everything else.
There was a discussion about this very topic quite recently, perhaps you can find it through the search.

Dependency injection and inheritance

Given:
class abstract AbstractFoo
MyObject obj;
class ConcreteFoo extends AbstractFoo
Now, I'd like to declare @EJB on "MyObject obj" but AbstractFoo is extended by other subclasses on the client end (outside the container) and so I don't want them to have any EJB3 dependencies. Is there a way for me to declare, inside ConcreteFoo, that "MyObject obj" should have @EJB associated with it?
Thanks,
Gili

Hi Janeth,
As you can see, Web Dynpro is not a standar JEE container so itu2019s not possible to use dependency injection from a Web Dynpro layer. You have to use JNDI lookups as usually.
Perhaps the following link may help you: https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/605ff5f2-e589-2910-3ead-e558376e6f3d
You can use EJB Web Dynpro models as an alternative.
Edited by: Sergi Arrufat on Jun 3, 2008 12:27 PM

EJB 3.0 client side dependency injection

Hi,
I develop an EJB 3.0 based enterprise application using Sun Java System Application Server. The application includes a Swing based client to be launched via Java WebStart. The client has to access some of the EJBs. Is it possible to use dependency injection on client side (see the @EJB annotation) and if yes how do I set the properties for this?
The following snipped hopefully explains what I mean. The class FastEntry is a class of the Swing client. My question is how can I get the deviceSessionBean initialized?
public class FastEntry extends javax.swing.JFrame {
@EJB
private static DeviceSessionRemote deviceSessionBean;Kind regards,
Matthias

Hi,
For callbacks and interceptors, you can look at this page : http://today.java.net/pub/a/today/2005/08/18/ejb3.html
For sending messages, I'd recommend to use JMS (if in clientSide), or EJB3 Message beans if in server side.
Hope that helps :)

EJB 3.0 Why Dependency Injection doesn't work?

Hello Every body,
i have a serious problem with dependency injection with EJB 3.0. I have tried so many time to get the simple sun delivered samples ejb-Applications working in NetBeans IDE, but they don't. After importing in building the projects in NetBeans, i get a NullPointerException while trying to run them. Is there any body who have experience with this? What am i making wrong?
I searched for an answer since several days in google without any success. I have not found a single satisfactory explanation. I can't explain why even the examples in the java ee tutorials don't work.
Please, can somebody help? I would very greatful.
Cheers
flips
Here is an example of application (that don't work because the injection failed):
* This is the business interface for Confirmer enterprise bean.
@Remote
public interface Confirmer {
void sendNotice(String recipient);
@Stateless
public class ConfirmerBean implements Confirmer {
private static final String mailer = "JavaMailer";
private static Logger logger = Logger.getLogger(
"confirmer.ejb.ConfirmerBean");
@Resource(name = "mail/myMailSession")
private Session session;
/** Creates a new instance of ConfirmerBean */
public ConfirmerBean() {
public void sendNotice(String recipient) {
try {
Message message = new MimeMessage(session);
message.setFrom();
message.setRecipients(
Message.RecipientType.TO,
InternetAddress.parse(recipient, false));
message.setSubject("Test Message from ConfirmerBean");
DateFormat dateFormatter = DateFormat.getDateTimeInstance(
DateFormat.LONG,
DateFormat.SHORT);
Date timeStamp = new Date();
String messageText = "Thank you for your order." + '\n'
+ "We received your order on "
+ dateFormatter.format(timeStamp) + ".";
message.setText(messageText);
message.setHeader("X-Mailer", mailer);
message.setSentDate(timeStamp);
// Send message
Transport.send(message);
logger.info("Mail sent to " + recipient + ".");
} catch (MessagingException ex) {
ex.printStackTrace();
logger.info("Error in ConfirmerBean for " + recipient);
* @author ie139813
public class ConfirmerClient {
@EJB
private static Confirmer confirmer;
/** Creates a new instance of ConfirmerClient */
public ConfirmerClient() {
* @param args the command line arguments
public static void main(String[] args) {
String recipient = null;
if (args.length == 1) {
recipient = args[0];
} else {
recipient = "[email protected]";
try {
confirmer.sendNotice(recipient);
System.out.println("Message sent to " + recipient + ".");
System.exit(0);
} catch (Exception ex) {
ex.printStackTrace();
}

Try rebooting your computer. I had something similar. I rebooted my computer and it finished the update. Good luck!

EJB 3.0 Dependency Injection and reentrant Calls on SFSB

Hi there
I have a SFSB (Bean A) that injects another SFSB (Bean B) with the @EJB annotation. Now Bean A does reentrant-calls on Bean B, which is ok, because it just asks for the current state.
This results in a "javax.ejb.EJBTransactionRolledbackException: Illegal attempt to make a reentrant call to a stateful session bean from home: .....; nested exception is: javax.ejb.ConcurrentAccessException: Illegal attempt to make a reentrant call to a stateful session bean: ....."
Now I added a weblogic-ejb-jar.xml with the section:
<stateful-session-descriptor>
<allow-concurrent-calls>true</allow-concurrent-calls>
</stateful-session-descriptor>to enable reentrant calls on my SFSB. Unfortunatly this leads to problems with the DI, it simply doesnt work anymore!!! The message now is " java.lang.IllegalStateException: Cannot find object BeanBInterface with java:comp/env/ejb/BeanBInterface". Obviously the DI didn't work, the local variable isn't filled anmyore.
Is this a bug of WLS 10.0 MP1 or a feature? Should I open a bug report? Any tips a welcome!
Stephan

There is currently no possiblity in Weblogic 10 server web layer to use Dependency Injection on any other component than the ones defined in web.xml s.a.:
- servlets
- listeners
- filters
See here:
http://e-docs.bea.com/wls/docs100/webapp/annotateservlet.html
A simple POJO class part of the web application (such as a Backing Bean in JSF or an Action in Struts for example) is not benefiting from DI.
Doesn't this make Weblogic 10 a NON JEE 5 compliant server?
Why was this restriction imposed?
And how is one supposed to use DI with a simple POJO class? Why this huge inconvenience?

Question about dependent projects (and their libraries) in 11g-Oracle team?

Hello everyone,
I have a question about dependent projects. An example:
In JDeveloper 10.1.3.x if you had for instance 2 projects (in a workspace): project 1 has one project library (for instance a log4j library) and project 2 is a very simple webapplication which is dependent on project 1. Project 2 has one class which makes use of log4j.
This compiles fine, you can run project 2 in oc4j, and the libraries of project 1 (log4j) are added on the classpath and everything works fine. This is great for rapid testing as well as keeping management of libraries to a minimum (only one project where you would update a library e.g.)
However in 11g this approach seems not to work at all anymore now that weblogic is used, not even when 'export library' is checked in project 1. The library is simply never exported at all - with a noclassdeffound error as result. Is this approach still possible (without having to define multiple deployment profiles), or is this a bug?
Thanks!
Martijn
Edited by: MartijnR on Oct 27, 2008 7:57 AM

Hi Ron,
I've tried what you said, indeed in that .beabuild.txt when 'deploy by default' is checked it adds a line like: C:/JDeveloper/mywork/test2/lib/log4j-1.2.14.jar = test2-view-webapp/WEB-INF/lib/log4j-1.2.14.jar
Which looks fine, except that /web-inf/lib/ is empty. I presume its a sort of mapping to say: Load it like it in WEB-INF/lib? This line is not there when the deploy by default is not checked.
I modified the TestBean as follows (the method that references Log4j does it thru a Class.forName() now only):
public String getHelloWorld() {
try {
Class clazz = Class.forName("org.apache.log4j.Logger");
System.out.println(clazz.getName());
catch(Exception e) {
e.printStackTrace();
return "Hello World";
In both cases with or without line, it throws:
java.lang.ClassNotFoundException: org.apache.log4j.Logger
     at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:283)
     at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:256)
     at weblogic.utils.classloaders.ChangeAwareClassLoader.findClass(ChangeAwareClassLoader.java:54)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
     at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:176)
     at weblogic.utils.classloaders.ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:42)
     at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Class.java:169)
     at nl.test.TestBean.getHelloWorld(TestBean.java:15)
Secondly I added weblogic.xml with your suggested code, in the exploded war this results in a weblogic.xml which looks like:
<?xml version = '1.0' encoding = 'windows-1252'?>
<weblogic-web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.bea.com/ns/weblogic/weblogic-web-app.xsd" xmlns="http://www.bea.com/ns/weblogic/weblogic-web-app">
<container-descriptor>
<prefer-web-inf-classes>true</prefer-web-inf-classes>
</container-descriptor>
<jsp-descriptor>
<debug>true</debug>
<working-dir>/C:/JDeveloper/mywork/test2/view/classes/.jsps</working-dir>
<keepgenerated>true</keepgenerated>
</jsp-descriptor>
<library-ref>
<library-name>jstl</library-name>
<specification-version>1.2</specification-version>
</library-ref>
<library-ref>
<library-name>jsf</library-name>
<specification-version>1.2</specification-version>
</library-ref>
</weblogic-web-app>
The only thing from me is that container-descriptor tag, the rest is added to it during the deployment. Unfortunately, it still produces the same error. :/ Any clue?

About Dependency Injection in EJB3.0

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