I have an EJB with some JPA logic that I use in my java EE projects.
Instead of copying the class in every project I'm trying to put it in a separate jar, so I have this structure:
Java EE project with EJB and WAR projects in it
JPALogic: JAR project with JPALogic class in it
RemoteServices: JAR project with beans interfaces
Services: EJB project with beans, including JPALogic and RemoteServices as libraries
Frontend: WAR project with frontend, including RemoteServices as library.
JPALogic is used only in the EJB project and there's no reference to it in other parts of the Java EE app. In JPALogic library I've my JPALogic bean:
#Stateless
#LocalBean
public class JPALogic {
#Resource
private EJBContext ejbContext;
#Inject #ShardedPersistenceContext
private EntityManager em;
public JPALogic() {
}
[...lots of methods...]
}
It works perfect if JPALogic code is directly in the EJB project, but when I put it in the external library deployment become very unstable (netbeans 8 + glassfish 4) and almost every deploy fail with this error:
Exception while deploying the app [app] : Cannot resolve reference [Remote ejb-ref name=com.my.autenticacion.services.AutRolBackendServices/jpa,Remote 3.x interface =com.my.infraestructura.jpa.JPALogic,ejb-link=null,lookup=,mappedName=,jndi-name=,refType=Session] because there are [2] ejbs in the application with interface com.my.infraestructura.jpa.JPALogic.
I've search but it seems this kind of error appear when an interface have more than one implementation, and this is not the case: there's only one bean named "JPALogic" and, inspecting the ear, JPALogic.jar appear one time only.
I'm doing something wrong?
If you jar contains EJB annotations (#Singleton, #Stateless, #Stateful component-defining annotations), its not a simple jar, but an ejb-jar, and should be packaged as a module.
Solution:
You should reference the JPALogic.jar in application.xml as an EJB module.
You can also add a "Class-Path: JPALogic.jar" in the META-INF/MANIFEST.MF of the referencing modules to garantee visibility. It could be visibile, depending on the container.
Like this:
application.EAR
META-INF/application.xml
(must have a reference to the JPALogic.jar EJB module)
JPALogic.jar (EJB-JAR)
remoteservices.jar
services.jar
META-INF/MANITESF.MF Class-Path: JPALogic.jar
remoteservices.jar
frontend.war
For a more details, refer to the JAVA EE 6 specification, chapter EE.8:
EE.8.3.2 EJB Container Class Loading Requirements
EE.8.5.2 Deploying a Java EE Application
Related
We got Java EE 7 project with the following structure:
app.ear
META-INF
application.xml
lib
framework.jar
webapp.war
core.jar
Framework.jar is our framework that uses some kind of command pattern.
This is how it works. Each command has it's own ejb attached to it that does all the business logic. This command ejb extends CommandEJB class that have an execute method.
For example, this is an example of a command ejb:
public class cmdCreateBookEJB<T extends cmdCreateBook> extends CommandEJB<T> {
#Override
public void execute() {
//do something
}
}
And in our framework, we also have CommandExecutorEJB that sets the appropriate ejb for the command and execute it.
Example:
CmdCreateBook cmdCreateBook = new cmdCreateBook();
cmdCreateBook.setEjb(cmdCreateBookEJB.class.getSimpleName());
commandExecutorEJB.execute(cmdCreateBook);
The problem is our framework, specifically CommandExecutorEJB(that is packed in framework.jar inside lib folder) needs to know about ejb's from core.jar, so it can handle the command. What actually happens in the framework is that the the specific command ejb(cmdCreateBookEJB) in my example is cast to CommandEJB and then it's execute method is called.
The question is how to make the framework know about command ejbs.
I know that one option is to specify am env-entry in ejb-jar.xml with the core jar module name, and then use #Resource in commandExecutorEJB to find the entry, and then use the JNDI lookup to find the resource that would be cast to CommandBean.
But, I would like not to use ejb-jar.xml as we're using ejb 3.2 and ejb-jar.xml isn't necessary anymore.
EDIT:
To better explain here is how the jndi lookup string would look like for my example: java:app/core.jar/cmdCreateBookEJB
Because framework isn't and shouldn't be aware of the core.jar(The name core.jar name is just an example, someone could name it BookStoreCore.jar), I somehow need to pass module name(in my example core.jar), so that the framework know where to look for classes to find a specific command EJB, in my example cmdCreateBookEJB.
I know that I can use an env-var in ejb-jar.xml to pass module name to the framework. Here's an example:
<session>
<ejb-name>CommandExecutorEJB</ejb-name>
<ejb-class>com.mypackage.CommandExecutorEJB</ejb-class>
<session-type>Stateless</session-type>
<env-entry>
<env-entry-name>com.mypackage.CommandExecutorEJB/moduleName</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>core</env-entry-value>
</env-entry>
</session>
But, I would love to eliminate ejb-jar.xml from our project setup
You're using Java EE 7.
You can completely avoid class visibility problems by putting everything in your WAR file. core.jar and framework.jar can both be added to your WEB-INF/lib directory.
You can then directly inject EJBs where ever they're needed.
I have a strange problem with EJB injection in the glassfish 3. Maybe I just not completely understand what I do :)
So this is a problem: My project consists of 2 modules that will be assembled with gradle.
Module A
Module B
Module A is a usual glassfish module that also works fine. Module B contains general purpose staff. Module B is also a dependency of A. Module A will be deployed to glassfish as a *.war archive and Module B is in the appropriate lib folder as *.jar archive:
module-a.war and somewere inside of it ../lib/module-b.jar
What I want is: Create in the Module B a "general purpose" stateless bean and use it in the Module A. But it doesn't work...
In the Module B I created a bean:
#Stateless
public class GeneralPurposeBean {}
and I try to use it in the Module A as follows:
...
#EJB
private GeneralPurposeBean genPurpBean;
...
So how I already mentioned the GeneralPurposeBean is in the *.jar
Each time when I try to use the bean it fails with following exception:
javax.ejb.CreateException: Could not create stateless EJB
When I move the bean to the Module A it works fine but I want share this bean with other modules, that will be developed in the future. Can someone explain to me what is wrong here? So the bean will be recognized but it can't be created. What I found out through debugging is that
JCDIServiceImpl#_createJCDIInjectionContext
Doesn't recognize the bean as an enterprise bean. So everything in the *.war that directly accessible will be properly created but not what lies in the *.jar's.
For the case someone has the same problem:
If you treat one of your modules as a dependency and this module contains EJB beans you want be injected the solution for my problem was to put /META-INF/beans.xml file into the module. Otherwise container doesn't recognize the beans as EJB.
That's it.
I have an EJB deployed in an EAR:
#Stateless
#Remote(ActorProvider.class)
public class ActorServiceClient implements Serializable, ActorProvider { ... }
Here is the remote interface:
#Remote
public interface ActorProvider { ... }
Now, I have a separate WAR being deployed with the following class:
#Singleton
#Startup
public class ShiroStartup implements IShiroStartup {
#EJB
ActorProvider actorProvider;
...
}
The idea being that I deploy my actor service in an EAR, and I separately deploy a client project that gets the ActorProvider which Shiro uses for authorization (this is ancillary, but what I'm using it for).
I get an error starting the ShiroStartup (after I have deployed the EAR with the provider in it):
No EJB found with interface of type 'consumers.ActorProvider' for binding realm.ShiroStartup/actorProvider
Why can't I do this? If I put the Provider in the war with the ShiroStartup it works fine, but it will not inject across deployments. Why is that? This is Wildfly 9 using JavaEE 7.
1., The EJB and WAR modules should take place in the same EAR
or
2., Include the EJB jar into the classpath of the WAR
or :)
3., with portable JNDI names (for remote interfaces):
https://docs.oracle.com/cd/E19798-01/821-1841/girgn/index.html
In particular: java:app[/module name]/enterprise bean name[/interface name]
I am building a project for a class that I am taking, and it consists of 4 modules
-impl (business logic/dao access)
-ejb (encapsulates business logic and provides access to it via a remote interface)
-war (web tier)
-ear (contains the war and ejb modules)
One utility class that I have inside the impl is able to populate an H2 database. It does this by running an ingestor that reads in an processes an xml file that resides in a maven repository, using various dao classes/methods to ingest the data:
String fileName = "xml/proj-data.xml";
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);
When I run the ingestor through a unit test, it runs fine, but when I have everything layered, I get the NoClassDefFoundException on xml/proj-data.xml
So the basic outline that I have is:
-the war has dependencies on the impl and ejb modules
-the ejb has dependency on the impl module
-the ear has dependency on the impl, ejb, and war
This is a maven project. When I deploy the EAR to the server, the start page for the war is displayed (as I expect).
-The html page has a button that when pressed, does a post to a servlet
-The servlet has an ejb injected into it that it calls (via its remote interface).
-The ejb method makes a call back to the populate method in the impl, and thats when the exception happens, and I get a webpage back showing the exception.
Do I need to declare that repository in the WAR pom file as well?
In typing the question, I think I know what the problem may be. The repository that the xml file resides in is declared in the root pom for the project(the impl parent), NOT the pom for the impl module. Since the impl is the module that gets packaged with the EAR, I may need to declare the repository in the impl pom file as well.
The issue I am currently experiencing is that my entityManager fails to be injected during the execution of a web application deployed within an ear.
The ear is setup as follows:
/META-INF -application.xml (EJBJar +
WAR)
-MANIFEST.MF
-weblogic-application.xml (currently just the default one that eclipse
generates)
/APP-INF
-lib
-EJBClientJar (interfaces + pojos)
-other jars
-classes
EJBJar
/META-INF
-persistence.xml
/src
-Annotated classes
WAR
-Service classes
Classes are as follows:
DAO inside EJBJar
#Stateless(mappedName="AwesomeBean")
public class Awesome implements AwesomeRemote //AwesomeRemote in EJBClientJar
{
#PersistenceContext
EntityManager em;
}
public class AwesomeService //Inside WAR
{
AwesomeRemote = context.lookup (Awesome.path.to.AwesomeRemote) //Is found
}
The call stack is like this:
War -> EJBClientJar -> EJBJar
On the EJB jar the entity manager is null. Question being how do I ensure that the PersistenceContext gets injected? The JNDI lookup succeeds on the AwesomeRemote Interface. The Interface has no annotations on it.
It's probably due to the fact that you try to inject on POJO class, not on managed component. Could you try to mark it as #Stateless and public and check whether it works?
For simple testing you can also add #WebService annotation and invoke your bean with SoapUI for example.
You should read about "packaging" part of ejb specifications.
This structure should be sufficient and work:
/
/lib
EJBClientJar (interfaces + pojos)
/META-INF
persistence.xml
application.xml
EJBJar.jar
WAR.war
As some formatting was lost, I'm not sure about what wasn't right in yours.
If this still doesn't work, try removing the only tricky part from above: put all classes from EJBClientJar in root. You the just have the most simple EAR packaging possible, it just will work.
Also, if you don't use your session bean outside a web application, you could use #Local instead of #Remote .