Non matching type for inject of field

[James Hannoy]

Hi,

I am playing with EJB3 and using the following configuration:

JBoss 4.2.2 GA, EJB3/JPA, Oracle.

Here follows a simple session bean and its remote interface that I've been using:

@Remote
public interface Monitor {

public State create(String id, float in, int r,int b);
public State findById(String id);
 
}
 

@Stateless
@Remote(Monitor.class)
public class MonitorBean implements Monitor {
 
@PersistenceUnit(name = "StateMonitor")
private EntityManager em;
 
public State create(String id, float in, int r, int b) {
 
final State state = new State(id, in, r, b, Calendar.getInstance().getTime());
 
em.persist(state);
return state;
}

 
public State findById(String id) {
return em.find(State.class, id);
}
}

The PU named "StateMonitor" is mentioned and the same is also mentioned in
my persistence.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0"
xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence <a href="http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">" target="_blank" rel="nofollow">http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"></a>
 

<persistence-unit name="StateMonitor">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:/OracleDS</jta-data-source>
 
<properties>
<property name="hibernate.dialect"
value="org.hibernate.dialect.Oracle10gDialect" />
<property name="hibernate.hbm2ddl.auto" value="create-drop" />
</properties>
 
</persistence-unit>
</persistence>

Finally here follows a typical test client:

import javax.naming.Context;
import javax.naming.NamingException;
import javax.persistence.EntityManager;
 
import session.MonitorRemote;
import entity.CPUUsage;
import entity.IOUsage;
import entity.MemUsage;
import entity.Details;
import entity.SwapUsage;
 
public class TestClient {
 
private EntityManager em;
 
MonitorRemote dao = null;
 
public void runTest() throws Exception {
 
try {
Context jndiContext = getInitialContext();
Object ref = jndiContext.lookup("MonitorBean/remote");
dao = (MonitorRemote) ref;

DataProvider dp = new DataProvider();
 
CPUUsage c = new CPUUsage(dp.getCs(), dp.getUs(), dp.getSy(),
dp.getIdcpu(), dp.getWa());
MemUsage m = new MemUsage(dp.getSwapd(), dp.getFree(), dp
.getBuff(), dp.getCache());
IOUsage i = new IOUsage(dp.getBi(), dp.getBo());
SwapUsage s = new SwapUsage(dp.getSi(), dp.getSo());
 
Details o = new Details(dp.getOsname(), dp.getOsversion(),
dp.getOsbuild(), dp.getNoofcpus(), dp
.getNoofcpucores());
 
System.out.println("MonitorRemote Sateless...");
 
dao.create(dp.getId(), o, c, i, m, s, dp.getIn(), dp.getR(),
dp.getB());
dao.toString();
dao.findById(dp.getId());
dao.toString();
 
} catch (NamingException e) {
e.printStackTrace();
}
 
}
 

public static Context getInitialContext()
throws javax.naming.NamingException {
return new javax.naming.InitialContext();
}
 
public static void main(String[] args) {
try {
TestClient cli = new TestClient();
System.out.println("Created Class...");
cli.runTest();
 
} catch (Exception e) {
e.printStackTrace();
}
}
}

All these are very similar like any other simple project. The deployment shows no error and the table also get created in the DB.

But, whenever I try to run this simple client, I get the following error:

E:\E_WSPACE_EURO\StateMonitor>ant run.client
Buildfile: build.xml
 
prepare:
 
compile:
 
ejbjar:
 
run.client:
     [java] Created Class...
     [java] MonitorRemote Sateless...
     [java] java.lang.RuntimeException: Non matching type for inject of field: p
rotected javax.persistence.EntityManager session.MonitorBean.em for type: org.
jboss.ejb3.entity.InjectedEntityManagerFactory of jndiName env/session.Monitor
Bean/em
     [java] intfs: , javax.persistence.EntityManagerFactory, java.io.Externaliza
ble
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:128)
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:106)
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:63)
     [java]     at org.jboss.ejb3.AbstractPool.create(AbstractPool.java:111)
     [java]     at org.jboss.ejb3.InfinitePool.get(InfinitePool.java:49)
     [java]     at org.jboss.ejb3.ThreadlocalPool.create(ThreadlocalPool.java:50
)
     [java]     at org.jboss.ejb3.ThreadlocalPool.get(ThreadlocalPool.java:90)
     [java]     at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(
StatelessInstanceInterceptor.java:54)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.security.AuthenticationInterceptor.invoke(A
uthenticationInterceptor.java:77)
     [java]     at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(
Ejb3AuthenticationInterceptor.java:110)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagatio
nInterceptor.java:46)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(As
ynchronousInterceptor.java:106)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(Sta
telessContainer.java:304)
     [java]     at org.jboss.aop.Dispatcher.invoke(Dispatcher.java:106)
     [java]     at org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invok
e(AOPRemotingInvocationHandler.java:82)
     [java]     at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:76
9)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.processInvoc
ation(ServerThread.java:573)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.dorun(Server
Thread.java:373)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.run(ServerTh
read.java:166)
     [java] Caused by: java.lang.IllegalArgumentException
     [java]     at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFie
ldAccessorImpl.java:63)
     [java]     at java.lang.reflect.Field.set(Field.java:656)
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:116)
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:106)
     [java]     at org.jboss.injection.JndiFieldInjector.inject(JndiFieldInjecto
r.java:63)
     [java]     at org.jboss.ejb3.AbstractPool.create(AbstractPool.java:111)
     [java]     at org.jboss.ejb3.InfinitePool.get(InfinitePool.java:49)
     [java]     at org.jboss.ejb3.ThreadlocalPool.create(ThreadlocalPool.java:50
)
     [java]     at org.jboss.ejb3.ThreadlocalPool.get(ThreadlocalPool.java:90)
     [java]     at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(
StatelessInstanceInterceptor.java:54)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.security.AuthenticationInterceptor.invoke(A
uthenticationInterceptor.java:77)
     [java]     at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(
Ejb3AuthenticationInterceptor.java:110)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagatio
nInterceptor.java:46)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(As
ynchronousInterceptor.java:106)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(Sta
telessContainer.java:304)
     [java]     at org.jboss.aop.Dispatcher.invoke(Dispatcher.java:106)
     [java]     at org.jboss.aspects.remoting.AOPRemotingInvocationHandler.invok
e(AOPRemotingInvocationHandler.java:82)
     [java]     at org.jboss.remoting.ServerInvoker.invoke(ServerInvoker.java:76
9)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.processInvoc
ation(ServerThread.java:573)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.dorun(Server
Thread.java:373)
     [java]     at org.jboss.remoting.transport.socket.ServerThread.run(ServerTh
read.java:166)
     [java]     at org.jboss.remoting.MicroRemoteClientInvoker.invoke(MicroRemot
eClientInvoker.java:163)
     [java]     at org.jboss.remoting.Client.invoke(Client.java:1634)
     [java]     at org.jboss.remoting.Client.invoke(Client.java:548)
     [java]     at org.jboss.aspects.remoting.InvokeRemoteInterceptor.invoke(Inv
okeRemoteInterceptor.java:62)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.tx.ClientTxPropagationInterceptor.invoke(Cl
ientTxPropagationInterceptor.java:67)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.security.SecurityClientInterceptor.invoke(S
ecurityClientInterceptor.java:53)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInte
rceptor.java:74)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.stateless.StatelessRemoteProxy.invoke(Stateles
sRemoteProxy.java:107)
     [java]     at $Proxy0.create(Unknown Source)
     [java]     at testcases.TestClient.runTest(TestClient.java:46)
     [java]     at testcases.TestClient.main(TestClient.java:78)
     [java]     at org.jboss.aspects.remoting.InvokeRemoteInterceptor.invoke(Inv
okeRemoteInterceptor.java:74)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.tx.ClientTxPropagationInterceptor.invoke(Cl
ientTxPropagationInterceptor.java:67)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.aspects.security.SecurityClientInterceptor.invoke(S
ecurityClientInterceptor.java:53)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInte
rceptor.java:74)
     [java]     at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInv
ocation.java:101)
     [java]     at org.jboss.ejb3.stateless.StatelessRemoteProxy.invoke(Stateles
sRemoteProxy.java:107)
     [java]     at $Proxy0.create(Unknown Source)
     [java]     at testcases.TestClient.runTest(TestClient.java:46)
     [java]     at testcases.TestClient.main(TestClient.java:78)
 
BUILD SUCCESSFUL
Total time: 1 second
E:\E_WSPACE_EURO\StateMonitor>

Could someone guide me in here?
Any help would be greatly appreciated.

-Thanks,
James.

[James Hannoy]

So, anybody can give me some pointers to check or any ideas please?

-Thanks,
James.

[Jaikiran Pai]

James,

I don't see any obvious reasons why this should fail. I looked up a similar issue in JBoss JIRA and the comments there seemed to point to classloading issues. Maybe you too are running into a similar issue. What classes have you packaged in your client application? Do you have the MonitorBean packaged in your client application? If so, i would suggest removing that and having only the Monitor interface in the client application. See if that change helps. Let us know if it still doesn't work, we'll see what else might be the cause of this exception.

[Jaikiran Pai]

And which version of Java do you use at the client and on the server?

[James Hannoy]

Hi,

Thanks a lot for the reply. Yes I have also seen the Jira posts and was trying a lot of options. Surprisingly the following worked!!!

In my session bean code I have changed PersistenceUnit to PersistenceContext:

@Stateless
@Remote(MonitorRemote.class)
public class MonitorBean implements MonitorRemote {
 
// @PersistenceUnit(unitName = "StateMonitor")
@PersistenceContext(unitName = "StateMonitor")
private EntityManager em;
 

And it started working, but with some limitations.
Here follows my client code:

 
public class TestClient {
 
OSMonitorRemote dao = null;
 
public void runTest() throws Exception {
 
try {
Context jndiContext = getInitialContext();
Object ref = jndiContext.lookup("OSMonitorBean/remote");
dao = (OSMonitorRemote) ref;
 
DataProvider dp = new DataProvider();
 
System.out.println("OSMonitorRemote Sateless...");
OSState os = dao.create(dp.getId(), dp.getIn(), dp.getR(), dp.getB());
System.out.println("Created: " + os.toString());
 
System.out.println("OS ID: " + os.getId());
System.out.println("dp.getId(): " + dp.getId());

os = dao.findById(dp.getId());
System.out.println("Found: " + os.toString());
 
} catch (Exception e) {
e.printStackTrace();
}
 
}
 

public static Context getInitialContext()
throws javax.naming.NamingException {
return new javax.naming.InitialContext();
}
 
public static void main(String[] args) {
try {
TestClient cli = new TestClient();
System.out.println("Created Class...");
cli.runTest();
 
} catch (Exception e) {
e.printStackTrace();
}
}
 
}
 

And here follows the output:

run.client:
     [java] Created Class...
     [java] MonitorRemote Sateless...
     [java] Created: OS Name: Linux, OS Version: 2.6, OS Build: build 220
     [java] Total Number of CPUs: 4, number of cores per CPU: 4
     [java] CPU Usage: CS: 39.0, US: 2.0, SY: 2.0
     [java] ID: 96.0, WA: 0.0
     [java] I/O Usage: BI: 7.0, BO: 1.0
     [java] Memory Usage: SwapUsage: 53760.0, Free: 1124472.0, Buffer: 0.0, Cach
e: 0.0
     [java] Swap Usage: SI: 14.0, SO: 60.0
     [java] R: 0
     [java] java.lang.NullPointerException
     [java] B: 0
     [java]     at testcases.TestClient.runTest(TestClient.java:50)
     [java] IN: 62.0
     [java]     at testcases.TestClient.main(TestClient.java:77)
     [java] OS ID: 1
     [java] dp.getId(): 1

As you can see, the create works ( or may be, since toad shows no data in the table though!), but when I try to search the same with the same ID, it throws a null pointer!!

Do I have to use transactions??

Also the @PersistenceUnit and @PersistenceContext things are confusing



Could you please explain?

-Thanks,
James.

[James Hannoy]

Also I'm using JDK5 E:\jdk1.5.0_03... for the project.
-Thanks,
James.

[James Hannoy]

Hi Jaikiran,

Once more, to answer your original question, these are the imports in my TestClient:

package testcases;
 
import javax.naming.Context;
import javax.persistence.EntityManager;
 
import session.MonitorRemote;
.....
.....
public class TestClient {
....
....

So there is no reference of the MonitorBean session directly.

-Thanks
Pranabesh.

[James Hannoy]

Hi,

I have resolved the NullPointer issue. Actually, I changed the <jta-data-source>java:/OracleDS</jta-data-source> to <non-jta-data-source>java:/OracleDS</non-jta-data-source>, which created the problem.

Once I reverted back to <jta-data-source>java:/OracleDS</jta-data-source> in persistence.xml, everything worked fine.

However, I'd be grateful if you can answer my other queries/confusions.

Thanks!
James.

[Jaikiran Pai]

Good to know, you were able to get it working

As for your questions:

Also the @PersistenceUnit and @PersistenceContext things are confusing

The PersistenceUnit and the PersistenceContext inject different 'types' of resources. The @PersistenceUnit is used to inject an EntityManagerFactory whereas the @PersistenceContext is used to inject an EntityManager. In one of the online documentation that i read, they had this detailed explanation:

The @PersistenceContext and @PersistenceUnit annotations perform a similar function: inject persistence context information into a variable; the main difference is the data type of the instance into which you inject the information. If you prefer to have full control over the lifecycle of the EntityManager in your session bean, then use @PersistenceUnit to inject into an EntityManagerFactory instance, and then write the code to manually create an EntityManager and later destroy when you are done, to release resources. If you prefer that the EJB container manage the lifecycle of the EntityManager, then use the @PersistenceContext annotation to inject directly into an EntityManager.

Your other question:

Do I have to use transactions??

It depends on what you are doing. EJBs let you define transactions on each method of the bean. Moreover, if you are using a EntityManager, then you will have to have a transaction.
[ December 27, 2007: Message edited by: Jaikiran Pai ]

[James Hannoy]

Thanks a lot Jaikiran.


This explains all of these!

-Regards,
James.