Static variable in session bean

Can we declare static variable in session bean. If we declare what will happen. Will it create error in compile time or not deployed in server.

From a Java language perspective, nothing stops you from declaring a static variable in a session
bean class. It will compile as long as its syntactically correct.
From an EJB programming model perspective, the use of non-final static variables
is discouraged because it breaks the JVM-transparency that is an important aspect of the
EJB architecture. It should be possible to deploy a single EJB application to a cluster and
have it behave exactly as if it were deployed to only one server instance (albeit with higher
overall throughput/performance). Using non-final static variables breaks this property
because the bean instances in one JVM will see a different value for the static variable
than bean instances in a different JVM.
It also forces you to deal with synchronization
of the shared data, which is a complexity that was carefully avoided in the EJB programming
model by ensuring that each bean instance is single-threaded.
Bottom line is you can have "final static" data members in EJB classes but you should
avoid non-final (mutable) static data.
--ken

Similar Messages

Static methods in Session Beans problem

Can a Stateful Session Bean have a static method?
public static String foo();
I tried to add a static method to a Stateful Session bean but had two problems:
When I tried to add the static modifier to the Remote interface:
static String foo();
I got the following error message:
Error(12,17): modifier static not allowed here
When I tried to compile code calling this function :
MyClass.foo();
I got this message:
Error(795,42): non-static method getNewSuffix(java.lang.String) cannot be referenced from a static context
Even though a static method was compiled in this class. I assume it can't find the static modifier in the Remote interface which wasn't allowed. Are static methods allowed in EJB's at all?

dear friend,
1) Interfaces may not contain static functions!
2) EJBs doesnt support static methods !
Maybe you should go and learn more about Java and EJB's ?

Session Bean Destroy property

When a user logs out y proyect and go back to the sign up page, the sessionbean that contains the profile (int) stays with the same value, i have 6 variables (strings, int, integer, etc) in session bean, every time i use logout button i have to initialize the variables in session bean at once, i used sessionbean1.destroy(); but it doesnt work, anybody can tell me if im using well this?

The comments for the session bean's destroy method say:
 * This method is called when this bean is removed from
 * session scope. Typically, this occurs as a result of
 * the session timing out or being terminated by the application.
 * You may customize this method to clean up resources allocated
 * during the execution of the <code>init()</code> method, or
 * at any later time during the lifetime of the application.
 */This says that the web app automatically calls destroy() when the user session times out due to inactivity, or when the web application invalidates the session, such as, for example, by calling session.invalidate().
So, this does not appear to meet your needs as you want the variables to be nulled out when the user logs out (which does not necessarily end the session).
One other approach would be to create a session bean method, such as logout() that clear out the 6 variables.
Then have your logout button call this method, such as getSessionBean1().logout().
Another approach is to create a Java class, such as User with 6 properties.
Instantiate a User in the session bean when the user logs in
User user = new User();
and set user to null when the user logs out.

Stateful session bean destroying instance variables?

I'm trying to use a stateful session bean as some kind of login controller and to maintain the login id and access level across JSPs and HTMLs so that once logged in, all the JSPs can obtain the login name of the current user (String) and his access level (int).
I use the login.jsp to login and it successfully reports logging in with the correct access level retrieved from database. However, if I go to another JSP (testlogin.jsp), these 2 EJB instance variables are always destroyed and set to null and 0 when I access them again.
What am I missing that my stateful session bean is not saving these instance variables? Do I need to put them in some serializable value objects (create a help VO class?)
I suspected that on different JSP, I call the MemberControllerHome.create() method, it creates a new instance or something but if I don't use the create method how do I get a handle to MemberController at all?
MemberControllerBean.java
public class MemberControllerBean implements SessionBean {
 //initialize in ejbCreate.
 private MemberHome memberHome;
 SessionContext context;
 //Member currentLogin;
 //Current Login
 private String loginID;
 private int accessLevel;
 // Constructor
 public MemberControllerBean() {}
...some code in between...
public void login(String id, String password){
 try{
 Member member = null;
 member = memberHome.findByPrimaryKey(id);
 if(member.getMPassword().equals(password)){
 this.loginID = member.getMID();
 this.accessLevel = member.getMAccessLevel();
 else{
 throw new EJBException("Login failed. Invalid member ID and/or password.");
 } catch (FinderException ex) {
 throw new EJBException("Login failed. Invalid member ID and/or password.");
 public void logout(){
 this.loginID = null;
 this.accessLevel = 4;
 public String getLoginID(){
 return this.loginID;
 public int getLoginAccessLevel(){
 return this.accessLevel;
login.jsp
String mID = request.getParameter("mID");
String mPassword = request.getParameter("mPassword");
out.println("20:" + mID + ":" + mPassword);
if(mID != null && mPassword != null){
 out.println("22:" + mID + ":" + mPassword);
 try{
 InitialContext ic = new InitialContext();
 MemberControllerHome home = (MemberControllerHome) ic.lookup("java:comp/env/ejb/MemberController");
 MemberController mc = home.create();
 out.println("26:Logging in as " + mID + " with " + mPassword);
 mc.login(mID, mPassword);
 out.println("28:" + mc.getLoginID() + "logged in successfully at level " +
 mc.getLoginAccessLevel() + ".");
 } catch (NamingException ex) {
 out.println("java:comp/env/ejb/MemberController not found.");
 } catch (EJBException ex) {
 out.println(ex.getMessage());
 } catch (Exception ex) {
 out.println(ex.getMessage());
testlogin.jsp
<%
try{
 InitialContext ic = new InitialContext();
 MemberControllerHome home = (MemberControllerHome) ic.lookup("java:comp/env/ejb/MemberController");
 MemberController mc = home.create();
 out.println("You are logged in as " + mc.getLoginID() +
 " at level " + mc.getLoginAccessLevel() + ".");
} catch (NamingException ex) {
 out.println("java:comp/env/ejb/MemberController not found.");
} catch (EJBException ex) {
 out.println(ex.getMessage());
} catch (Exception ex) {
 out.println(ex.getMessage());
%>

The key to the problem is that in testlogin.jsp a new stateful session bean is created. The new bean instance of course doesn't know the log-in information you stored in the old session bean. That is why the method returns null and 0 when called.
There are couple of ways to solve the issue. The easiest solution is to store the bean instance created in Login.jsp in the jsp's implicit HttpSession object. Because login.jsp and testlogin.jsp share the same session, the bean instance can be easily stored and retrieved.
Here is the code you need to have:
1. in login.jsp
session.setAttribute("MemberControllerBeanInstance", mc);
2. in testlogin.jsp
MemberController mc =
(MemberController) session.getAttribute("MemberControllerBeanInstance");
Hope it helps.

Hi, I have quick question about use of USEBEAN tag in SP2. When I specify a scope of SESSION for the java bean, it does not keep the values that I set for variable in the bean persistent.Thanks,Sonny

Make sure that your bean is implementing the serializable interface and that
you are accessing the bean from the session with the same name.
Bryan
"Sandeep Suri" <[email protected]> wrote in message
news:[email protected]..
Hi, I have quick question about use of USEBEAN tag in SP2. When I
specify a scope of SESSION for the java bean, it does not keep the
values that I set for variable in the bean persistent.Thanks,Sonny
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How to get and set a session variable from backing bean?

Hi im using Jdev 11.1.1.2.0 and i need to set and get a session variable from backing Bean.
Any idea?

the class :
package arq.resources;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpSession;
public class SesionSigef {
public FacesContext context;
public HttpSession session;
public SesionSigef() {
super();
context = FacesContext.getCurrentInstance();
session = (HttpSession)(context.getExternalContext().getSession(true));
public Object getVariableSesion(String atributo){
return session.getAttribute(atributo);
public void setVariableSesion(String atributo,Object valor){
session.setAttribute(atributo, valor);
the example of use :
SesionSigef se = new SesionSigef();
DatosRec da = new DatosRec();
da.setDocumentoCip("Aprobar");
se.setVariableSesion("DatosRec", da);
thanks
Joaquin

Session Bean-static field or ejbCreate/Activate

Hi,
I have a stateful session bean whose methods use JDBC. I need to load the
JDBC driver.
Where is the best place to do this? static field, or one of the ejb
callbacks such as ejbCreate or ejbActivate.
Another way to put the question is, when a bean has been passivated and then
reactivated, do the static fields in bean class get initialized?
Thanx,
Mark

You should not be loading the JDBC driver explictly at all, but rather using
JNDI to get a connection from a managed connection pool. If you do the JDBC
directly, you're bypassing the transaction control for which you in all
likelihood have the appserver in the first place.
"mark" <[email protected]> wrote in message
news:3uhp8.60950$[email protected]..
Hi,
I have a stateful session bean whose methods use JDBC. I need to load the
JDBC driver.
Where is the best place to do this? static field, or one of the ejb
callbacks such as ejbCreate or ejbActivate.
Another way to put the question is, when a bean has been passivated andthen
reactivated, do the static fields in bean class get initialized?
Thanx,
Mark

Re: static variables in beans

That's GoF. Again I was responding to the question posted earlier and could not
see it near by and not commenting on yours. I was questioning the original design
of having to keep singletons as static fields in SLSBs.
S
"Cameron Purdy" <[email protected]> wrote:
Is there a problem if you get the singleton (through a static methodas
in GoF) objects in the methods as required and not store it as static
variables in the SLSB?I am acronymically challened ("AC"). What is GoF? I know I've seen it
before, but I can't remember what it means.
Singletons should store their own reference. You should probably have
a
private constructor and a static "instance" accessor.
Peace,
Cameron Purdy
Tangosol, Inc.
http://www.tangosol.com/coherence.jsp
Tangosol Coherence: Clustered Replicated Cache for Weblogic
"sri" <[email protected]> wrote in message news:[email protected]..
>

You are right. An EJB (all kinds) is restricted from using writtable static fields.
Read only fields are allowed but recommended to use 'final' to denote so.
S
"Cameron Purdy" <[email protected]> wrote:
That's GoF. Again I was responding to the question posted earlier and
could not see it near by and not commenting on yours. I was questioning
the original design of having to keep singletons as static fields inSLSBs.
It gets difficult to follow these threads. I use Outlook Express (motto:
"There's no message out there that we can't add a top-post to!") which
isn't
the world's best newsreader.
Regarding static fields in SLSBs, you are right that it is certainly
something to avoid. I believe that some containers even refuse to deploy
EJBs that have static fields like that. (I believe it's a purposed
limitation in the spec.)
Peace,
Cameron Purdy
Tangosol, Inc.
http://www.tangosol.com/coherence.jsp
Tangosol Coherence: Clustered Replicated Cache for Weblogic
"Sri" <[email protected]> wrote in message news:3ea5b88e$[email protected]..
>

JDEV 10.1.3 How to manipulate/Debug IndirectList from ejb 3.0 session bean

I was debugging my session bean a seen that element data for the employeesCollection was empty.
I didn't understood why my java client was throwing an error when i accessed manually the Departments collection and get the employeeCollection from the first entry in the collection. What was confusing me was that my master/detail jfs application was displaying these data. From where ? how was it possible ? it was the same session bean !
This is the reason i debugged the session bean return object and seen that the collection was also empty as the from executing from my java client application. I have seen the type of the object that was not a collection but IndirectList.
So my question ! how is it possible to load the collection of this type ? Which method the data control is executing to load it ? Where may i found a description of this very interesting process ?

Hi Frank.
plain English - on plan :).
I create managed bean with function which do access to LDAP and this function 'return List<Users>'.
In JDeveloper :) on managed bean(java class) i create "Create Data Control"... after, from Data Controls i drop on page this data(create ADF Table with selectOne)...
First Page Ready!
Second page... i need to know which option selected on first page. This option(row) contains, UserName and etc... On second page i again fetch data, from LDAP, associated with this concrete UserName... Because i fetch data using managed bean :) i need to know this username in my managed bean...
May be :) im wrong...
sessionAttribute - like this? ->
* Convenience method for setting Session variables
* @param ctx FacesContext
* @param key object key
* @param object value to store
public static void storeOnSession(FacesContext ctx, String key, Object object) {
Map sessionState = ctx.getExternalContext().getSessionMap();
sessionState.put(key, object);
* Convenience method for getting Session variables
* @param ctx FacesContext
* @param key object key
public static Object getFromSession(FacesContext ctx, String key) {
Map sessionState = ctx.getExternalContext().getSessionMap();
return sessionState.get(key);
}

HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean

HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean
by Steve Muench
Overview
BC4J provides automatic facilities for deploying any application module as a stateful EJB session bean. If you want to leverage the features of your BC4J application module from a stateless EJB session bean, it's not automatic but it is straightforward to implement. This howto article explains the details.
For our example, we will create a stateless EJB session bean that uses a container-managed transaction. To keep things simple, let's assume the session bean has a single public method on its remote interface named createDepartment() with the following signature:
public void createDepartment(int id, String name, String loc) throws AppException
AppException is an example of an application-specific exception that our method will throw if any problems arise during its execution.The goal of this article is to illustrate how to use the BC4J application module named com.example.hr.HRApp as part of the implementation of this createDepartment method on our stateless enterprise bean. Let's assume that the HRApp application module has a view object member named Departments, based on the com.example.hr.DeptView view object, based on the familiar DEPT table and related to the com.example.hr.Dept entity object so our view can be updateable.
Creating the Stateless Session Bean
We can start by using the JDeveloper Enterprise Bean wizard to create a new stateless session bean called StatelessSampleEJB implemented by:[list][*]com.example.StatelessSampleEJBBean (Bean class)[*]com.example.StatelessSampleEJBHome (Home interface)[*]com.example.StatelessSampleEJB (Remote interface)[list]
We then use the EJB Class Editor to add the createDepartment method to the remote interface of StatelessSampleEJB with the signature above. We edit the remote interface to make sure that it also reflects that the createDepartment method thows the AppException like this:
package com.example;
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
public interface StatelessSampleEJB extends EJBObject {
void createDepartment(int id, String name, String loc)
throws RemoteException,AppException;
}Before we start adding BC4J into the picture for our implementation, our StatelessSampleEJBBean class looks like this:
package com.example;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
public class StatelessSampleEJBBean implements SessionBean {
public void ejbCreate(){}
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){
public void createDepartment(int id, String name, String loc)
throws AppException {
 // TODO: Implement method here
}We can double-click on the ejb-jar.xml file in our project to see the XML deployment descriptor for the bean we just created:
<ejb-jar>
 <enterprise-beans>
 <session>
 <description>Session Bean ( Stateless )</description>
 <display-name>StatelessSampleEJB</display-name>
 <ejb-name>StatelessSampleEJB</ejb-name>
 <home>com.example.StatelessSampleEJBHome</home>
 <remote>com.example.StatelessSampleEJB</remote>
 <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
 <session-type>Stateless</session-type>
 <transaction-type>Container</transaction-type>
 </session>
 </enterprise-beans>
</ejb-jar>We need to add the extra <assembly-descriptor> section in this file to indicate that the createDepartment method will require a transaction. After this edit, the ejb-jar.xml file looks like this:
<ejb-jar>
 <enterprise-beans>
 <session>
 <description>Session Bean ( Stateless )</description>
 <display-name>StatelessSampleEJB</display-name>
 <ejb-name>StatelessSampleEJB</ejb-name>
 <home>com.example.StatelessSampleEJBHome</home>
 <remote>com.example.StatelessSampleEJB</remote>
 <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
 <session-type>Stateless</session-type>
 <transaction-type>Container</transaction-type>
 </session>
 </enterprise-beans>
 <assembly-descriptor>
 <container-transaction>
 <method>
 <ejb-name>StatelessSampleEJB</ejb-name>
 <method-name>createDepartment</method-name>
 <method-params>
 <method-param>int</method-param>
 <method-param>java.lang.String</method-param>
 <method-param>java.lang.String</method-param>
 </method-params>
 </method>
 <trans-attribute>Required</trans-attribute>
 </container-transaction>
 </assembly-descriptor>
</ejb-jar>
Aggregating a BC4J Application Module
With the EJB aspects of our bean setup, we can proceed to implementing the BC4J application module aggregation.
The first thing we do is add private variables to hold the EJB SessionContext and the instance of the aggregated BC4J ApplicationModule, like this:
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private SessionContext _ctx = null;and we modify the default, empty implementation of the setSessionContext() method to remember the session context like this:
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }We add additional constants that hold the names of the J2EE datasource that we want BC4J to use, as well as the fully-qualified name of the BC4J application module that we'll be aggregating:
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";We expand the now-empty ejbCreate() and ejbRemove() methods to create and destory the aggregated instance of the BC4J application module that we'll use for the lifetime of the stateless session bean. When we're done, ejbCreate() it looks like this:
public void ejbCreate() throws CreateException {
try {
 // Setup a hashtable of environment parameters for JNDI initial context
 Hashtable env = new Hashtable();
 env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
 // NOTE: we want to use the BC4J app module in local mode as a simple Java class!
 env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
 env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
 // Create an initial context, using this hashtable of environment params
 InitialContext ic = new InitialContext(env);
 // Lookup a home interface for the application module
 ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
 // Using the home, create the instance of the appmodule we'll use
 _am = home.create();
 // Register the BC4J factory to handle EJB container-managed transactions
 registerContainerManagedTransactionHandlerFactory();
catch(Exception ex) {
 ex.printStackTrace();
 throw new CreateException(ex.getMessage());
}and ejbRemove() looks like this:
public void ejbRemove() {
try {
 // Cleanup any appmodule resources before getting shutdown
 _am.remove();
catch(JboException ex) { /* Ignore */ }
}The helper method named reigsterContainerManagedTransactionHandlerFactory() looks like this:
private void registerContainerManagedTransactionHandlerFactory() {
SessionImpl session = (SessionImpl)_am.getSession();
session.setTransactionHandlerFactory(
 new TransactionHandlerFactory() {
 public TransactionHandler createTransactionHandler() {
 return new ContainerManagedTxnHandlerImpl();
 public JTATransactionHandler createJTATransactionHandler() {
 return new ContainerManagedTxnHandlerImpl();
}The last detail is to use the BC4J appmodule to implement the createDepartment() method. It ends up looking like this:
public void createDepartment(int id, String name, String loc)
throws AppException {
try {
 // Connect the AM to the datasource we want to use for the duration
 // of this single method call.
 _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
 // Use the "Departments" view object member of this AM
 ViewObject departments = _am.findViewObject("Departments");
 // Create a new row in this view object.
 Row newDept = departments.createRow();
 // Populate the attributes from the parameter arguments.
 newDept.setAttribute("Deptno", new Number(id));
 newDept.setAttribute("Dname", name);
 newDept.setAttribute("Loc", loc);
 // Add the new row to the view object's default rowset
 departments.insertRow(newDept);
 // Post all changes in the AM, but we don't commit them. The EJB
 // container managed transaction handles the commit.
 _am.getTransaction().postChanges();
catch(JboException ex) {
 // To be good EJB Container-Managed Transaction "citizens" we have
 // to mark the transaction as needing a rollback if there are problems
 _ctx.setRollbackOnly();
 throw new AppException("Error creating dept "+ id +"\n"+ex.getMessage());
finally {
 try {
 // Disconnect the AM from the datasource we're using
 _am.getTransaction().disconnect();
 catch(Exception ex) { /* Ignore */ }
Building a Test Client
With the EJB-Tier work done, we can build a sample client program to test this new stateless EJB Session Bean by selecting the bean in the Oracle9i JDeveloper IDE and choosing "Create Sample Java Client" from the right-mouse menu.
When the "Sample EJB Client Details" dialog appears, we take the defaults of connecting to embedded OC4J container. Clicking the (OK) button generates the following test class:
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;
import com.example.StatelessSampleEJB;
import com.example.StatelessSampleEJBHome;
public class SampleStatelessSampleEJBClient {
public static void main(String [] args) {
 SampleStatelessSampleEJBClient sampleStatelessSampleEJBClient =
 new SampleStatelessSampleEJBClient();
 try {
 Hashtable env = new Hashtable();
 env.put(Context.INITIAL_CONTEXT_FACTORY,
 "com.evermind.server.rmi.RMIInitialContextFactory");
 env.put(Context.SECURITY_PRINCIPAL, "admin");
 env.put(Context.SECURITY_CREDENTIALS, "welcome");
 env.put(Context.PROVIDER_URL,
 "ormi://localhost:23891/current-workspace-app");
 Context ctx = new InitialContext(env);
 StatelessSampleEJBHome statelessSampleEJBHome =
 (StatelessSampleEJBHome)ctx.lookup("StatelessSampleEJB");
 StatelessSampleEJB statelessSampleEJB;
 // Use one of the create() methods below to create a new instance
 // statelessSampleEJB = statelessSampleEJBHome.create();
 // Call any of the Remote methods below to access the EJB
 // statelessSampleEJB.createDepartment( int id, java.lang.String name, java.lang.String loc );
 catch(Throwable ex) {
 ex.printStackTrace();
}We uncomment the call to the create() method and add a few calls to the createDepartment() method so that the body of the test program now looks like this:
// Use one of the create() methods below to create a new instance
statelessSampleEJB = statelessSampleEJBHome.create();
// Call any of the Remote methods below to access the EJB
statelessSampleEJB.createDepartment( 13, "Test1","Loc1");
System.out.println("Created department 13");
statelessSampleEJB.createDepartment( 14, "Test2","Loc2");
System.out.println("Created department 14");
try {
// Try setting a department id that is too large!
statelessSampleEJB.createDepartment( 23456, "Test3","Loc3");
catch (AppException ax) {
System.err.println("AppException: "+ax.getMessage());
}Before we can successfully run our SampleStatelessSampleEJBClient we need to first run the EJB bean that the client will try to connect to. Since Oracle9i JDeveloper supports local running and debugging of the EJB-Tier without doing through a full J2EE deployment step, to accomplish this prerequisite step we just need to right-mouse on the StatelessSampleEJB node in the System Navigator and select "Run". This starts up the embedded OC4J instance and runs the EJB right out of the current out path.Finally, we can run the SampleStatelessSampleEJBClient, and see the output of the test program in the JDeveloper log window:
Created department 13
Created department 14
AppException: Error creating dept 23456
JBO-27010: Attribute set with value 23456 for Deptno in Dept has invalid precision/scale
Troubleshooting
One error that might arise while running the example is that the database connection information in your data-sources.xml for the jdbc/OracleCoreDS datasource does not correspond to the database you are trying to test against. If this happens, then double-check the file .\jdev\system\oc4j-config\data-sources.xml under the JDeveloper installation home directory to make sure that the url value provided is what you expect. For example, to work against a local Oracle database running on your current machine, listening on port 1521, with SID of ORCL, you would edit this file to have an entry like this for jdbc/OracleCoreDS :
<data-source
 class="com.evermind.sql.DriverManagerDataSource"
 name="OracleDS"
 location="jdbc/OracleCoreDS"
 xa-location="jdbc/xa/OracleXADS"
 ejb-location="jdbc/OracleDS"
 connection-driver="oracle.jdbc.driver.OracleDriver"
 username="scott"
 password="tiger"
 url="jdbc:oracle:thin:@localhost:1521:ORCL"
 inactivity-timeout="30"
/>This is the data-sources.xml file that gets used by the embedded OC4J instance running in JDeveloper.
Conclusion
Hopefully this article has illustrated that it is straightforward to utilize the full power of BC4J in local mode as part of your EJB Stateless Session Beans using container-managed transaction. This example illustrated a single createDepartment method in the enterprise bean, but by replicating the application module interaction code that we've illustrated in createDepartment, any number of methods in your stateless session bean can use the aggregated application module instance created in the ejbCreate() method.
Code Listing
The full code listing for the SampleStatelessEJB bean implementation class looks like this:
* StatelessSampleEJB
* Illustrates how to use an aggregated BC4J application module
* in local mode as part of the implementation of a stateless
* EJB session bean using container-managed transaction.
* HISTORY
* smuench/dmutreja 14-FEB-2002 Created
package com.example;
import oracle.jbo.*;
import oracle.jbo.server.*;
import javax.ejb.*;
import oracle.jbo.domain.Number;
import oracle.jbo.common.PropertyConstants;
import java.util.Hashtable;
import javax.naming.InitialContext;
import oracle.jbo.server.ejb.ContainerManagedTxnHandlerImpl;
public class StatelessSampleEJBBean implements SessionBean {
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private SessionContext _ctx = null;
public void ejbCreate() throws CreateException {
 try {
 // Setup a hashtable of environment parameters for JNDI initial context
 Hashtable env = new Hashtable();
 env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
 env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
 env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
 // Create an initial context, using this hashtable of environment params
 InitialContext ic = new InitialContext(env);
 // Lookup a home interface for the application module
 ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
 // Using the home, create the instance of the appmodule we'll use
 _am = home.create();
 // Register the BC4J factory to handle EJB container-managed transactions
 registerContainerManagedTransactionHandlerFactory();
 catch(Exception ex) {
 ex.printStackTrace();
 throw new CreateException(ex.getMessage());
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }
public void createDepartment(int id, String name, String loc)
throws AppException {
 try {
 // Connect the AM to the datasource we want to use for the duration
 // of this single method call.
 _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
 // Use the "Departments" view object member of this AM
 ViewObject departments = _am.findViewObject("Departments");
 // Create a new row in this view object.
 Row newDept = departments.createRow();
 // Populate the attributes from the parameter arguments.
 newDept.setAttribute("Deptno", new Number(id));
 newDept.setAttribute("Dname", name);
 newDept.setAttribute("Loc", loc);
 // Add the new row to the view object's default rowset
 departments.insertRow(newDept);
 // Post all changes in the AM, but we don't commit them. The EJB
 // container managed transaction handles the commit.
 _am.getTransaction().postChanges();
 catch(JboException ex) {
 // To be good EJB Container-Managed Transaction "citizens" we have
 // to mark the transaction as needing a rollback if there are problems
 _ctx.setRollbackOnly();
 throw new AppException("Error creating dept "+ id +\n"+ex.getMessage());
 finally {
 try {
 // Disconnect the AM from the datasource we're using
 _am.getTransaction().disconnect();
 catch(Exception ex) { /* Ignore */ }
private void registerContainerManagedTransactionHandlerFactory() {
 SessionImpl session = (SessionImpl)_am.getSession();
 session.setTransactionHandlerFactory(
 new TransactionHandlerFactory() {
 public TransactionHandler createTransactionHandler() {
 return new ContainerManagedTxnHandlerImpl();
 public JTATransactionHandler createJTATransactionHandler() {
 return new ContainerManagedTxnHandlerImpl();

Hi Steve, It4s me again;
About the question I made, I tried with a single assembly-descriptor tag and a single container-transaction tag in the deployment descriptor of the session bean and these were the results.
java.lang.NullPointerException
 void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
 java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
 void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Then I tried with multiple assembly-descriptor tags each with a single container-transaction tag and the results were:
java.lang.NullPointerException
 void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
 java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
 void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Finally I tried with a single assembly-descriptor and multiple container tags and the results were:
java.lang.NullPointerException
 void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
 java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
 void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
 void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
How can I make my Stateless Session bean work out?

Unable to call exported client methods of EJB session bean remote interface

I am unable to call client methods of a BC4J application module deployed as a Session EJB to Oracle 8i at the client side of my multi-tier application. There is no documentation, and I am unable to understand how I should do it.
A business components project has been created. For instance, its application module is called BestdataModule. A few custom methods have been added to BestdataModuleImpl.java file, for instance:
public void doNothingNoArgs() {
public void doNothingOneArg(String astr) {
public void setCertificate(String userName, String userPassword) {
theCertificate = new Certificate(userName, userPassword);
public String getPermission() {
if (theCertificate != null)
{if (theCertificate.getPermission())
{return("Yes");
else return("No, expired");
else return("No, absent");
theCertificate being a protected class variable and Certificate being a class, etc.
The application module has been tested in the local mode, made remotable to be deployed as EJB session bean, methods to appear at the client side have been selected. The application module has been successfully deployed to Oracle 8.1.7 and tested in the remote mode. A custom library containing BestdataModuleEJBClient.jar and BestDataCommonEJB.jar has been created.
Then I try to create a client basing on Example Oracle8i/EJB Client snippet:
package bestclients;
import java.lang.*;
import java.sql.*;
import java.util.*;
import javax.naming.*;
import oracle.aurora.jndi.sess_iiop.*;
import oracle.jbo.*;
import oracle.jbo.client.remote.ejb.*;
import oracle.jbo.common.remote.*;
import oracle.jbo.common.remote.ejb.*;
import oracle.jdeveloper.html.*;
import bestdata.client.ejb.*;
import bestdata.common.ejb.*;
import bestdata.common.*;
import bestdata.client.ejb.BestdataModuleEJBClient;
public class BestClients extends Object {
static Hashtable env = new Hashtable(10);
public static void main(String[] args) {
String ejbUrl = "sess_iiop://localhost:2481:ORCL/test/TESTER/ejb/bestdata.BestdataModule";
String username = "TESTER";
String password = "TESTER";
Hashtable environment = new Hashtable();
environment.put(javax.naming.Context.URL_PKG_PREFIXES, "oracle.aurora.jndi");
environment.put(Context.SECURITY_PRINCIPAL, username);
environment.put(Context.SECURITY_CREDENTIALS, password);
environment.put(Context.SECURITY_AUTHENTICATION, ServiceCtx.NON_SSL_LOGIN);
BestdataModuleHome homeInterface = null;
try {
Context ic = new InitialContext(environment);
homeInterface = (BestdataModuleHome)ic.lookup(ejbUrl);
catch (ActivationException e) {
System.out.println(e.getMessage());
e.printStackTrace();
System.exit(1);
catch (CommunicationException e) {
System.out.println(e.getMessage());
e.printStackTrace();
System.exit(1);
catch (NamingException e) {
System.out.println(e.getMessage());
e.printStackTrace();
System.exit(1);
try {
System.out.println("Creating a new EJB instance");
RemoteBestdataModule remoteInterface = homeInterface.create();
// Method calls go here!
// e.g.
// System.out.println(remoteInterface.foo());
catch (Exception e) {
System.out.println(e.getMessage());
e.printStackTrace();
It doesnt cause any errors. However, how must I call methods? The public interface RemoteBestdataModule has no such methods:
void doNothingNoArgs();
void doNothingOneArg(java.lang.String astr);
void setCertificate(java.lang.String userName, java.lang.String userPassword);
java.lang.String getPermission();
Instead of that it has the following methods:
oracle.jbo.common.remote.PiggybackReturn doNothingNoArgs(byte[] _pb) throws oracle.jbo.common.remote.ejb.RemoteJboException, java.rmi.RemoteException;
oracle.jbo.common.remote.PiggybackReturn doNothingOneArg(byte[] _pb, java.lang.String astr) throws oracle.jbo.common.remote.ejb.RemoteJboException, java.rmi.RemoteException;
oracle.jbo.common.remote.PiggybackReturn customQueryExec(byte[] _pb, java.lang.String aQuery) throws oracle.jbo.common.remote.ejb.RemoteJboException, java.rmi.RemoteException;
oracle.jbo.common.remote.PiggybackReturn setCertificate(byte[] _pb, java.lang.String userName, java.lang.String userPassword) throws oracle.jbo.common.remote.ejb.RemoteJboException, java.rmi.RemoteException;
oracle.jbo.common.remote.PiggybackReturn getPermission(byte[] _pb) throws oracle.jbo.common.remote.ejb.RemoteJboException, java.rmi.RemoteException;
I cannot call those methods. I can see how they are called in BestdataModuleEJBClient.java file:
public void doNothingNoArgs() throws oracle.jbo.JboException {
try {
oracle.jbo.common.remote.PiggybackReturn _pbRet = mRemoteAM.doNothingNoArgs(getPiggyback());
processPiggyback(_pbRet.mPiggyback);
if (_pbRet.isReturnStreamValid()) {
return;
catch (oracle.jbo.common.remote.ejb.RemoteJboException ex) {
processRemoteJboException(ex);
catch (java.rmi.RemoteException ex) {
processRemoteJboException(ex);
throw new oracle.jbo.JboException("Marshall error");
However, I cannot call getPiggyback() function! It is a protected method, it is available to the class BestdataModuleEJBClient which extends EJBApplicationModuleImpl, but it is unavailable to my class BestClients which extends Object and is intended to extend oracle.jdeveloper.html.WebBeanImpl!
It seems to me that I mustnt use RemoteBestdataModule interface directly. Instead of that I must use the public class BestdataModuleEJBClient that extends EJBApplicationModuleImpl and implements BestdataModule interface. It contains all methods required without additional arguments (see just above). However, how must I create an object of BestdataModuleEJBClient class? That is a puzzle. Besides my custom methods the class has only two methods:
protected bestdata.common.ejb.RemoteBestdataModule mRemoteAM;
/*This is the default constructor (do not remove)*/
public BestdataModuleEJBClient(RemoteApplicationModule remoteAM) {
super(remoteAM);
mRemoteAM = (bestdata.common.ejb.RemoteBestdataModule)remoteAM;
public bestdata.common.ejb.RemoteBestdataModule getRemoteBestdataModule() {
return mRemoteAM;
It looks like the remote application module must already exist! In despair I tried to put down something of the kind at the client side:
RemoteBestdataModule remoteInterface = homeInterface.create();
BestdataModuleEJBClient dm = new BestdataModuleEJBClient(remoteInterface);
dm.doNothingNoArgs();
Of course, it results in an error.
System Output: null
System Error: java.lang.NullPointerException
System Error: oracle.jbo.common.PiggybackOutput oracle.jbo.client.remote.ApplicationModuleImpl.getPiggyForRemovedObjects(oracle.jbo.common.PiggybackOutput) (ApplicationModuleImpl.java:3017)
System Error: byte[] oracle.jbo.client.remote.ApplicationModuleImpl.getPiggyfront(boolea
System Error: n) (ApplicationModuleImpl.java:3059)
System Error: byte[] oracle.jbo.client.remote.ApplicationModuleImpl.getPiggyback() (ApplicationModuleImpl.java:3195)
System Error: void bestdata.client.ejb.BestdataModuleEJBClient.doNothingNoArgs() (BestdataModuleEJBClient.java:33)
System Error: void bes
System Error: tclients.BestClients.main(java.lang.String[]) (BestClients.java:76)
I have studied a lot of documents in vain. I have found only various senseless discourses:
"Use the Application Module Wizard to make the Application Module remotable and export the method. This will generate an interface for HrAppmodule (HrAppmodule.java in the Common package) which contains the signature for the exported method promoteAllEmps(). Then, deploy the Application Module. Once the Application Module has been deployed, you can use the promoteAllEmps() method in your client-side programs. Calls to the promoteAllEmps() method in client-side programs will result in calls to the promote() method in the application tier."
However, I have failed to find a single line of code explaining how it should be called.
Can anybody help me?
Best regards,
Svyatoslav Konovaltsev,
[email protected]
null

Dear Steven,
1. Thank you very much. It seems to me that the problem is solved.
2. "I logged into Metalink but it wants me to put in both a tar number and a country name to see your issue." It was the United Kingdom, neither the US nor Russia if you mean my issue.
I reproduce the text to be written by everyone who encounters the same problem:
package bestclients;
import java.util.Hashtable;
import javax.naming.*;
import oracle.jbo.*;
public class BestdataHelper {
public static ApplicationModule createEJB()
throws ApplicationModuleCreateException {
ApplicationModule applicationModule = null;
try {
Hashtable environment = new Hashtable(8);
environment.put(Context.INITIAL_CONTEXT_FACTORY, JboContext.JBO_CONTEXT_FACTORY);
environment.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_EJB);
environment.put(Context.SECURITY_PRINCIPAL, "TESTER");
environment.put(Context.SECURITY_CREDENTIALS, "TESTER");
environment.put(JboContext.HOST_NAME, "localhost");
environment.put(JboContext.CONNECTION_PORT, new Integer("2481"));
environment.put(JboContext.ORACLE_SID, "ORCL");
environment.put(JboContext.APPLICATION_PATH, "/test/TESTER/ejb");
Context ic = new InitialContext(environment);
ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup("bestdata.BestdataModule");
applicationModule = home.create();
applicationModule.getTransaction().connect("jdbc:oracle:kprb:@");
applicationModule.setSyncMode(ApplicationModule.SYNC_IMMEDIATE);
catch (NamingException namingException) {
throw new ApplicationModuleCreateException(namingException);
return applicationModule;
package bestclients;
import bestdata.common.*;
import certificate.*;
public class BestClients extends Object {
public static void main(String[] args) {
BestdataModule bestdataModule = (BestdataModule)BestdataHelper.createEJB();
Certificate aCertificate = new Certificate("TESTER", "TESTER");
//calling a custom method!!
bestdataModule.passCertificate(aCertificate);
Thank you very much,
Best regards,
Svyatoslav Konovaltsev.
[email protected]
null

Can I use static variable in EJB?

Many books suggest developer don't use static variable in EJB,I want to know why?
I know there isn't any problem if the static varibale is read only
For writable static varible ,what will happen if I use a static Hashtable for share data
Help me!Thank you very much!!

Greetings,
I know that "EJB business methods are not allowed to
block on synchronized resources" Just where do you "know" that from?? The EJB 2.0 Specification, at least, is nowhere in agrement with this statement. If it comes from a book I would question the author's reasoning. Contractually, there's no sound basis for this. In the case of Session Beans, they have an expressedly direct and single-threaded association with a client. From a design viewpoint, it certainly seems unnecessary for a bean to "block" its one-and-only client, but to say that it "is not allowed to" do so is without merit. Entity Beans, on the other hand, are concurrently accessible. Yet, with regard to a transactional context being in effect, the container does indeed block on a bean's business methods. For the bean to do so itself is, therefore, unnecessary. Furthermore, the specification explicitly concedes that a "Bean Provider is typically an application domain expert" and "is not required to be an expert at system-level programming." (EJB 2.0 Spec. 3.1.1) From these statements alone it is reasonable to assume the above statement is meritless since the Bean Provider is not expected to even consider synchronization issues when developing a bean.
But I'm mixed up why we could use "Hashtable" or otherApparently, because your sources are as well...
collection classes in the EJB ,in these method many
methods are synchronized In fact, not only "can we use" them but, with respect to multiple-row finders in Entity Beans we are [i]required to use them (or an iteration of them)! Not all Collection classes are synchronized (so called "heavy-weight collections"). As shown above, that the choice of a particular Collection class might be synchronized is of little consequence since a bean designed under strict adherence to the specification ensures that it is never concurrently writeable.
Could someone provide a good way for this problem?
Please Help Me!!!Regards,
Tony "Vee Schade" Cook

Global static variable. I just CANNOT get global for everything

Hi,
I copied a connection pool example from oracle web site. It uses static variable. Its not a servlet, its a javabean. I can run a million times in one session and everything is great. If I open up another session, it creates another instance and creates more connections when it should be seeing the previous instance.
My question is how to make a static variable global to the entire application? Do i have to initialize it in the servlet container? All im doing is calling a JSP page which calls this bean. If instance is null, create 5 new connections. Well like i stated above, it works for a single session. It appears that each session gets its own instance. I have been working and debugging this for a long time and I just cannot come up with a solution...
Any ideas???
Thanks as always

Declar it as static within the servlet class.
public class MyServlet extends HttpServlet {
public static ConnectionPool pool;
Then you can access it from any JSP/Servlet using MyServlet.pool but you may have to import the class into the JSP/Servlet.
Be aware that there may be synchroniztion issues when you access this static object so you may want to synchronize access to the pool.
synchronized (application) {
if (MyServlet.pool == null) { //initialize pool code here }

EJB 3.0 - Communicate an Applet with a Session Bean

Hello
I'm developing an EJB 3.0 app (eclipse and glassfish tools bundle), and I have an applet that has to use remote session beans.
QUESTION: Is it possible for the applet to connect to EJB?
QUESTION: By creating a J2EE application client project, can I use @EJB annotations to inject the session bean directly to the applet, avoiding the JNDI lookup?
(since I imagine that the anwser to the second one is NO, I do the following consideration)
Given an application client project, I imagine that this application can run remotely on a client machine/JRE. Then this application can use Annotations/injection facilities whenever it runs on a J2EE client container (which I assume consists of a set of libraries provided by the application server vendor, Glassfish in that case). Could this application be deployed using Java Web Start? If so, why can't it be deployed as an applet? (both options run in a client JRE, don't they?).
QUESTION: In either case (applet or JWS), how do I have to package the JAR file (using Eclipse) so that it contains the needed libraries for accessing the EJB? Which are those libraries?
At the time being, I'm trying to implement a sample application that follows the "Applet doing JNDI lookup" approach. I have:
- an EAR project
- an EJB project (containing an Entity Bean and a Stateless Session Bean with a @Remote interface)
@Remote
public interface HelloRemote {
 public String hello(String name);
@Stateless
public class Hello implements HelloRemote {
 @Override
 public String hello(String name) {
 return "Hello "+name+"!!";
}- an Application Client project (containing the applet code):
public class ClientApplet extends JApplet {
 public void init(){
 try {
 Context jndiContext = getInitialContext( );
 HelloRemote server = (HelloRemote) jndiContext.lookup(HelloRemote.class.getName());
 setContentPane(new JLabel(server.hello("Gerard")));
 } catch (NamingException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 private Context getInitialContext() throws NamingException{
 Properties props = new Properties();
 props.setProperty("java.naming.factory.initial", "com.sun.enterprise.naming.SerialInitContextFactory");
 props.setProperty("org.omg.CORBA.ORBInitialHost", "myhost");
 props.setProperty("org.omg.CORBA.ORBInitialPort", "3700");
 return new InitialContext(props);
}- a static web project (with a sample web page that contains the applet object the corresponding applet JAR file)
I tried to export the Application Client project as an "application client JAR", in the hope that the java EE libraries bundled with glassfish (listed as libraries of this project) would be packaged too.
No success, so now I'll try to copy all the JAR files (one by one) into the +\WebContent\+ folder of the Web Project, and add references to each of them in the archive="" attribute of the +<applet>+ HTML tag. Although this might work, I suspect that I am missing the good/easy way of doing it. Any suggestions?
Thanks in advance,
Gerard
Edited by: gsoldevila on May 6, 2009 7:09 AM

An Applet can communicate with an EJB via JNDI lookup but I would (personally) use an intermediate Servlet to handle this. Client to Servlet communication is http whereas to ejb is iiop - which might be blocked.
Injection only works in managed classes (EJB, Servlet, Listeners..) and an Application Client main class. So yes you could use an app client for handling resource injection.
m

Declarative Transactions, Session Beans & JDBC

Hi (this is really a newbie question),
If I executed an SQL Update statement in a Stateless Session Bean via JDBC,
is my call to the database enlisted in the container transaction
automatically? (Of course, I am assuming the correct TxRequired settings
are set on the deployment descriptors for the Session Bean.)
Asked in another way, how does JDBC "talk" to the EJB container to let it
know that it is being called within a Transactional Context and that all
activities with the database should then be enlisted in a transaction
automatically? Where does this "smartness" come in? Or does this not happen
at all - do I have to "obtain" the JDBC connection object from the EJB
container instead of writing directly to JDBC?
Thanks in advance,
Abdullah Kauchali

Correct.
I'd also recommend (where possible), doing the DataSource JNDI lookup in
your setSessionContext method and storing it away in a member variable.
There's usually no reason to do it on every method call.
-- Rob
Abdullah Kauchali wrote:
Okay,
After some investigations, this is what I've learned:
1. To get automatic transactional enlistment (in a distributed tx), you
have to make your EJB container aware of the JDBC datasource (viz. you have
to create a Transactional DataSource). This is done by creating necessary
entries in a configuration XML file so that the container can connect to the
JDBC datasource when fired-up;
2. You then only create your Connection object via a reference (JNDI to be
exact) to the connection object and NOT directly with JDBC (this was my
confusion in fact). Something like this:
//obtain the conduit to the JNDI resource manager factory
javax.sql.DataSource objDS = (javax.sql.DataSource)
context.lookup("~some jndi
reference~");
//now get the connection object - notice no "javax" but "java"
java.sql.Connection objCon = objDS.getConnection();
3. By doing 2. above you are actually using a "Resource Manager Connection
Factory" to get your Connection object for subsequent SQL Updates;
4. As long as your JDBC driver supports the javax.sql.DataSource interface
and provided Transactional Context is propagated from any root call to your
worker Session Bean, you get automatic transaction enlistment of the SQL
Updates with your EJB container;
Please correct me if I have concluded wrongly,
Regards
Abdullah
"Abdullah Kauchali" <ak@ak> wrote in message
news:[email protected]...
Hi (this is really a newbie question),
If I executed an SQL Update statement in a Stateless Session Bean viaJDBC,
is my call to the database enlisted in the container transaction
automatically? (Of course, I am assuming the correct TxRequired settings
are set on the deployment descriptors for the Session Bean.)
Asked in another way, how does JDBC "talk" to the EJB container to let it
know that it is being called within a Transactional Context and that all
activities with the database should then be enlisted in a transaction
automatically? Where does this "smartness" come in? Or does this nothappen
at all - do I have to "obtain" the JDBC connection object from the EJB
container instead of writing directly to JDBC?
Thanks in advance,
Abdullah Kauchali

Static variable in session bean

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