JNDI lookup error in MDB

[karthik kummar]

Hi Friends i am new to java beans. i am trying to implement Simple MDB using Netbean tool. but in client programming, i am getting error at JNDI lookup line. i am using JBOSS as server. my coding details are given below.

MDB code:

package model;

import javax.ejb.MessageDrivenBean;
import javax.ejb.MessageDrivenContext;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;


public class SimpleMessageBean implements MessageDrivenBean, MessageListener {
    
    private MessageDrivenContext context;

    public void setMessageDrivenContext(MessageDrivenContext aContext) {
        context = aContext;
    }

    public void ejbCreate() {
        // TODO Add code to acquire and use other enterprise resources (DataSource, JMS, enterprise bean, Web services)
    }

    public void ejbRemove() {

        // See section 15.7.3 of the EJB 2.1 specification
    }

 
    public void onMessage(Message aMessage) {
    
        
        TextMessage msg = null;

    try {
        if (aMessage instanceof TextMessage) {
            msg = (TextMessage) aMessage;
            System.out.println
                ("MESSAGE BEAN: Message received: " 
                + msg.getText());
        } else {
            System.out.println
                ("Message of wrong type: " 
                + aMessage.getClass().getName());
        }
    } catch (JMSException e) {
        e.printStackTrace();
       // mdc.setRollbackOnly();
    } catch (Throwable te) {
        te.printStackTrace();
    }
    }
}

ejb-jar.xml:

<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar version="2.1" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_2_1.xsd">
    <display-name>SimpleMDB-ejb</display-name>
    <enterprise-beans>
        <message-driven>
            <display-name>SimpleMessageBeanMDB</display-name>
            <ejb-name>SimpleMessageBean</ejb-name>
            <ejb-class>model.SimpleMessageBean</ejb-class>
            <transaction-type>Container</transaction-type>
            <message-destination-type>javax.jms.Queue</message-destination-type>
            <message-destination-link>jms/MyQueue</message-destination-link>
            <activation-config>
                <activation-config-property>
                    <activation-config-property-name>acknowledgeMode</activation-config-property-name>
                    <activation-config-property-value>Auto-acknowledge</activation-config-property-value>
                </activation-config-property>
                <activation-config-property>
                    <activation-config-property-name>destinationType</activation-config-property-name>
                    <activation-config-property-value>javax.jms.Queue</activation-config-property-value>
                </activation-config-property>
            </activation-config>
        </message-driven>
        </enterprise-beans>
    <assembly-descriptor>
        <container-transaction>
            <method>
                <ejb-name>SimpleMessageBean</ejb-name>
                <method-name>*</method-name>
            </method>
            <trans-attribute>Required</trans-attribute>
        </container-transaction>
        <message-destination>
            <display-name>Destination for SimpleMessageBeanMDB</display-name>
            <message-destination-name>jms/MyQueue</message-destination-name>
        </message-destination>
        </assembly-descriptor>
    </ejb-jar>

jboss.xml:

<?xml version="1.0" encoding="UTF-8"?>
<jboss>
  <enterprise-beans>
    <message-driven>
      <ejb-name>SimpleMessageBean</ejb-name>
      <destination-jndi-name>queue/jms/MyQueue</destination-jndi-name>
    </message-driven>
  </enterprise-beans>
</jboss>

client code:

package view;

import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;



public class SimpleMessageBeanClient {
      private static Queue queue = null;
  QueueConnectionFactory queueConnectionFactory = null;
  QueueConnection queueConnection = null;
  QueueSender queueSender = null;
  QueueSession queueSession = null;
    private TextMessage message=null;
    Context jndiContext;

  public SimpleMessageBeanClient(){
  try {
  //client creates the connection, session, and message sender:
   queueConnectionFactory = (QueueConnectionFactory)jndiContext.lookup("java:comp/env/jms/MyQueueConnectionFactory");
    queue = (Queue)jndiContext.lookup("java:comp/env/jms/QueueName");
    
    queueConnection = queueConnectionFactory.createQueueConnection();
    queueSession =queueConnection.createQueueSession(false,Session.AUTO_ACKNOWLEDGE);
    queueSender = queueSession.createSender(queue);
   
    message = queueSession.createTextMessage();

    for (int i = 0; i < 5; i++) {
     message.setText("This is message " + (i + 1));
     System.out.println("Sending message: " +
         message.getText());
     queueSender.send(message);
}

  System.out.println("Sending message"); 
 //session.close ();
  } catch (Exception e) {
  e.printStackTrace ();
  }
  }
  public static void main(String[] args)
  {
      SimpleMessageBeanClient sim = new SimpleMessageBeanClient();
  }
}

MDB is deploying without any error, but while run the client program 21st line searching for connection factory getting failed with error as null pointer exception whether i have to change in *.xml files. could you please advice on this.

[Andrew Moko]

karthik kummar wrote:Hi Friends i am new to java beans. i am trying to implement Simple MDB using Netbean tool. but in client programming, i am getting error at JNDI lookup line. i am using JBOSS as server. my coding details are given below.

MDB code:

package model;

import javax.ejb.MessageDrivenBean;
import javax.ejb.MessageDrivenContext;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;


public class SimpleMessageBean implements MessageDrivenBean, MessageListener {
    
    private MessageDrivenContext context;

    public void setMessageDrivenContext(MessageDrivenContext aContext) {
        context = aContext;
    }

    public void ejbCreate() {
        // TODO Add code to acquire and use other enterprise resources (DataSource, JMS, enterprise bean, Web services)
    }

    public void ejbRemove() {

        // See section 15.7.3 of the EJB 2.1 specification
    }

 
    public void onMessage(Message aMessage) {
    
        
        TextMessage msg = null;

    try {
        if (aMessage instanceof TextMessage) {
            msg = (TextMessage) aMessage;
            System.out.println
                ("MESSAGE BEAN: Message received: " 
                + msg.getText());
        } else {
            System.out.println
                ("Message of wrong type: " 
                + aMessage.getClass().getName());
        }
    } catch (JMSException e) {
        e.printStackTrace();
       // mdc.setRollbackOnly();
    } catch (Throwable te) {
        te.printStackTrace();
    }
    }
}

ejb-jar.xml:

<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar version="2.1" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_2_1.xsd">
    <display-name>SimpleMDB-ejb</display-name>
    <enterprise-beans>
        <message-driven>
            <display-name>SimpleMessageBeanMDB</display-name>
            <ejb-name>SimpleMessageBean</ejb-name>
            <ejb-class>model.SimpleMessageBean</ejb-class>
            <transaction-type>Container</transaction-type>
            <message-destination-type>javax.jms.Queue</message-destination-type>
            <message-destination-link>jms/MyQueue</message-destination-link>
            <activation-config>
                <activation-config-property>
                    <activation-config-property-name>acknowledgeMode</activation-config-property-name>
                    <activation-config-property-value>Auto-acknowledge</activation-config-property-value>
                </activation-config-property>
                <activation-config-property>
                    <activation-config-property-name>destinationType</activation-config-property-name>
                    <activation-config-property-value>javax.jms.Queue</activation-config-property-value>
                </activation-config-property>
            </activation-config>
        </message-driven>
        </enterprise-beans>
    <assembly-descriptor>
        <container-transaction>
            <method>
                <ejb-name>SimpleMessageBean</ejb-name>
                <method-name>*</method-name>
            </method>
            <trans-attribute>Required</trans-attribute>
        </container-transaction>
        <message-destination>
            <display-name>Destination for SimpleMessageBeanMDB</display-name>
            <message-destination-name>jms/MyQueue</message-destination-name>
        </message-destination>
        </assembly-descriptor>
    </ejb-jar>

jboss.xml:

<?xml version="1.0" encoding="UTF-8"?>
<jboss>
  <enterprise-beans>
    <message-driven>
      <ejb-name>SimpleMessageBean</ejb-name>
      <destination-jndi-name>queue/jms/MyQueue</destination-jndi-name>
    </message-driven>
  </enterprise-beans>
</jboss>

client code:

package view;

import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;



public class SimpleMessageBeanClient {
      private static Queue queue = null;
  QueueConnectionFactory queueConnectionFactory = null;
  QueueConnection queueConnection = null;
  QueueSender queueSender = null;
  QueueSession queueSession = null;
    private TextMessage message=null;
   [b] Context jndiContext;[/b]

  public SimpleMessageBeanClient(){
  try {
  //client creates the connection, session, and message sender:
   queueConnectionFactory = (QueueConnectionFactory)jndiContext.lookup("java:comp/env/jms/MyQueueConnectionFactory");
    queue = (Queue)jndiContext.lookup("java:comp/env/jms/QueueName");
    
    queueConnection = queueConnectionFactory.createQueueConnection();
    queueSession =queueConnection.createQueueSession(false,Session.AUTO_ACKNOWLEDGE);
    queueSender = queueSession.createSender(queue);
   
    message = queueSession.createTextMessage();

    for (int i = 0; i < 5; i++) {
     message.setText("This is message " + (i + 1));
     System.out.println("Sending message: " +
         message.getText());
     queueSender.send(message);
}

  System.out.println("Sending message"); 
 //session.close ();
  } catch (Exception e) {
  e.printStackTrace ();
  }
  }
  public static void main(String[] args)
  {
      SimpleMessageBeanClient sim = new SimpleMessageBeanClient();
  }
}

MDB is deploying without any error, but while run the client program 21st line searching for connection factory getting failed with error as null pointer exception whether i have to change in *.xml files. could you please advice on this.

It simply means You have a NPE AND You need to initialize the jndiContext and optionally pass in the environmental configuration variables to the constructor:

Context jndiContext = new InitialContext(); // use default environmental vars
or
jndiContext = new InitialContext(env); // env - configuration property file with env. variables.

[karthik kummar]

Hi,

I am used "Context jndiContext = new InitialContext();" class to initialize the JNDI. I am getting below mentioned error.

run:
javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file: java.naming.factory.initial
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:645)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:325)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at view.SimpleMessageBeanClient.<init>(SimpleMessageBeanClient.java:30)
at view.SimpleMessageBeanClient.main(SimpleMessageBeanClient.java:54)


I do not know how to configure property file with environment variables. so i did not tryied that.


Could you please advice on this to solve.

[James Boswell]

The standard set of JNDI properties are:


java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.provider.url=jnp://localhost:1099
java.naming.factory.url.pkgs=org.jboss.naming.client


These values may vary depending on your version of JBoss. They should be defined in a file called jndi.properties which is on the classpath when the client code runs.

[karthik kummar]

Hi,
I am not using to use JBOSSMQ. i am using JMS and deploying under JBOSS AS. I think we have to give the above mentioned JNDI config only for JBOSSMQ. may i correct?

i need to connect via my own connection factory and Queue. How to do this.

could you please advice on this.