EJB Application Client clarification

Question

Hi EJB Guru,
I would like some clarification on accessing Remote/Local Session Bean using an Application Client. In other word,
there appears to be more than one approach to the same Session bean. Let's start by declaring the Converter EJB:
package converter.ejb;
import java.math.BigDecimal;
import javax.ejb.Remote;
@Remote
public interface Converter {
    public BigDecimal dollarToYen(BigDecimal dollars);
    public BigDecimal yenToEuro(BigDecimal yen);
package converter.ejb;
import java.math.BigDecimal;
import javax.ejb.Stateless;
@Stateless
public class ConverterBean implements converter.ejb.Converter {
    private BigDecimal euroRate = new BigDecimal("0.0070");
    private BigDecimal yenRate = new BigDecimal("112.58");
    public BigDecimal dollarToYen(BigDecimal dollars) {
        BigDecimal result = dollars.multiply(yenRate);
        return result.setScale(2, BigDecimal.ROUND_UP);
    public BigDecimal yenToEuro(BigDecimal yen) {
        BigDecimal result = yen.multiply(euroRate);
        return result.setScale(2, BigDecimal.ROUND_UP);
}I have two method to accessing this bean.
( i ) Lookup JNDI using the following set of code:
package converter.client;
import converter.ejb.Converter;
import java.math.BigDecimal;
import javax.ejb.EJB;
import javax.naming.InitialContext;
import javax.naming.Context;
import javax.naming.NamingException;
public class ConverterClient {
    public static void main(String[] args) {
        try {
            InitialContext ctx = new InitialContext();
            ConverterRemote jndiconverter = (ConverterRemote) ctx.lookup("converter.ejb.ConverterRemote");
            BigDecimal param = new BigDecimal("100.00");
            BigDecimal yenAmount = jndiconverter.dollarToYen(param);
            System.out.println("$" + param + " is " + yenAmount + " Yen.");
            BigDecimal euroAmount = jndiconverter.yenToEuro(yenAmount);
            System.out.println(yenAmount + " Yen is " + euroAmount + " Euro.");
            System.exit(0);
        } catch (javax.naming.NamingException ne) {
            System.err.println("Caught an unexpected exception!");
            ex.printStackTrace();
}( ii ) Application Client lookup?
package converter.client;
import converter.ejb.Converter;
import java.math.BigDecimal;
import javax.ejb.EJB;
public class ConverterClient {
    @EJB
    private static Converter converter;
    /** Creates a new instance of Client */
    public ConverterClient(String[] args) {
    public static void main(String[] args) {
        ConverterClient client = new ConverterClient(args);
        client.doConversion();
    public void doConversion() {
        try {
            BigDecimal param = new BigDecimal("100.00");
            BigDecimal yenAmount = converter.dollarToYen(param);
            System.out.println("$" + param + " is " + yenAmount + " Yen.");
            BigDecimal euroAmount = converter.yenToEuro(yenAmount);
            System.out.println(yenAmount + " Yen is " + euroAmount + " Euro.");
            System.exit(0);
        } catch (Exception ex) {
            System.err.println("Caught an unexpected exception!");
            ex.printStackTrace();
}It is the first time I come a cross method ( ii ) and could not get it to work properly. The error message
received were:
SJSAS server side
**RemoteBusinessJndiName: converter.ejb.Converter; remoteBusIntf: converter.ejb.Converter
LDR5010: All ejb(s) of [converter] loaded successfully!
Registering ad hoc servlet: WebPathPath: context root = "/converter", path = "/converter-app-client'
Java Web Start services started for application com.sun.enterprise.appclient.jws.ApplicationContentOrigin@c91c07
registration name=converter
    [email protected]3900 registration name=converter, context
root=/converter/converter-app-client, module name=
, parent=converter
WEB0100: Loading web module [converter:converter-war.war] in virtual server [server] at [/converter]
Class [ Lconverter/ejb/Converter; ] not found. Error while loading [ class converter.client.ConverterClient ]
Error in annotation processing: java.lang.NoClassDefFoundError: Lconverter/ejb/Converter;
deployed with moduleid = converter-app-client
Converter-app-client side
Caught an unexpected exception!
java.lang.NullPointerException
        at converter.client.ConverterClient.doConversion(ConverterClient.java:59)
        at converter.client.ConverterClient.main(ConverterClient.java:53)Here is the JNDI listing in ASADMIN:
C:\>asadmin
Use "exit" to exit and "help" for online help.
asadmin> list-jndi-entries
Jndi Entries for server within root context:
converter.ejb.Converter: javax.naming.Reference
converter.ejb.Converter#converter.ejb.Converter: javax.naming.Reference
jbi: com.sun.enterprise.naming.TransientContext
jdbc: com.sun.enterprise.naming.TransientContext
UserTransaction: com.sun.enterprise.distributedtx.UserTransactionImpl
ejb: com.sun.enterprise.naming.TransientContext
converter.ejb.Converter__3_x_Internal_RemoteBusinessHome__: javax.naming.Reference
Command list-jndi-entries executed successfully.
asadmin>My questions are:
( a ) Why does the error occur?
( b ) what is the architecture difference in accessing the same bean? Does JNDI lookup allows one to access EJB from remote host as opposed the method ( ii ) which is only restricted to local access on the same JVM/Container?
( c ) What are the pros & cons between the two?
I am using Application Client to lookup these Session Beans on Netbeans 5.5, SJSAS 9.0, SDK 1.5.0_11 on Windows XP platform.
Any guideance/advice would be very much appreciated.
Thanks alot,
Henry

Answer 1

Hi, may be you can help me with a similar problem that I have, I transcript the post in the netbeans forum, I really hope that you or someone can help me with this. Thanks in advance!
I hope that somebody can help me solving this issue.
Environment:
NetBeans 6.0 beta1 + glassfish b58g fresh installed
Windows XP
Make a new enterprise application with application client. Run the empty Main and it runs ok.
Now create a Stateless Session Bean with hello method.
In the Application Client Main insert a reference to the EJB using the wizard. (@EJB etc...)
invoke the hello method from the main().
right click on libraries from application client and add the application-ejb project
Deploy and it deploys ok, but when you run it throws an exception:
client:
java.lang.NullPointerException
server:
Error in annotation processing: java.lang.NoClassDefFoundError: Lorg/arautos/revista/sacrae/server/business/SACRAEFacadeRemote;
java.io.FileNotFoundException: C:\opt\glassfish-v2-b58g\domains\domain1\applications\j2ee-modules\SACRAE-app-client\SACRAE-ejb.jar (El sistema no puede hallar el archivo especificado)
Remember we added the project to the appclient libraries. If I place the missing file in the applications directory of glassfish it wont work, because when you run it, deploying on the server will erase it again. But, if you copy the jar file in the directory and open it with 7zip or any other application that can keep the file open, when you run it again it will work (because the server is not able to delete the file).
Although this is a workaround, there should be something I am doing wrong to cause this behavior, now when I try to use Java Web Start to execute the client it fails (surprisingly) with this exception:
java.lang.reflect.InvocationTargetException
Caused by: java.lang.NoClassDefFoundError: org/arautos/revista/sacrae/server/business/SACRAEFacadeRemote
at org.arautos.revista.sacrae.client.desktop.Main.main(Main.java:30)
... 21 more
And I don't know where in the domain1 directory place the jar, worse, I don't know how to solve the issue with the ejb-jar in the first place, does anybody has an idea, link, same problem? I have googled, netbeans-ed and java.net-ed a lot but didn't find anything :(
Thanks in advance for any help.
Best Regards.