javax.naming.NoInitialContextException - Java [duplicate]

Question

Here is my code:

import javax.naming.InitialContext;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.QueueSender;
import javax.jms.DeliveryMode;
import javax.jms.QueueSession;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;

public class Sender
{
    public static void main(String[] args) throws Exception
    {
        // get the initial context
        InitialContext ctx = new InitialContext();

        // lookup the queue object
        Queue queue = (Queue) ctx.lookup("queue/queue0");

        // lookup the queue connection factory
        QueueConnectionFactory connFactory = (QueueConnectionFactory) ctx.
           lookup("queue/connectionFactory");

        // create a queue connection
        QueueConnection queueConn = connFactory.createQueueConnection();

        // create a queue session
        QueueSession queueSession = queueConn.createQueueSession(false,Session.DUPS_OK_ACKNOWLEDGE);

        // create a queue sender
        QueueSender queueSender = queueSession.createSender(queue);
        queueSender.setDeliveryMode(DeliveryMode.NON_PERSISTENT);

        // create a simple message to say "Hello"
        TextMessage message = queueSession.createTextMessage("Hello");

        // send the message
        queueSender.send(message);

        // print what we did
        System.out.println("sent: " + message.getText());

        // close the queue connection
        queueConn.close();
    }
}

Eclipse is not reporting any errors in the above code -- I'm able to compile successfully. However, when I try running it, I get the following exception:

Exception in thread "main" 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(Unknown Source)
  at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source)
  at javax.naming.InitialContext.getURLOrDefaultInitCtx(Unknown Source)
  at javax.naming.InitialContext.lookup(Unknown Source)
  at Sender.main(Sender.java:21)

Can anyone please help me fix the bug? I tried fixing it for a few hours but still cannot figure it out.

Answer 1

We need to specify the INITIAL_CONTEXT_FACTORY, PROVIDER_URL, USERNAME, PASSWORD etc. of JNDI to create an InitialContext.

In a standalone application, you can specify that as below

Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY, 
    "com.sun.jndi.ldap.LdapCtxFactory");
env.put(Context.PROVIDER_URL, "ldap://ldap.wiz.com:389");
env.put(Context.SECURITY_PRINCIPAL, "joeuser");
env.put(Context.SECURITY_CREDENTIALS, "joepassword");

Context ctx = new InitialContext(env);

But if you are running your code in a Java EE container, these values will be fetched by the container and used to create an InitialContext as below

System.getProperty(Context.PROVIDER_URL);

and

these values will be set while starting the container as JVM arguments. So if you are running the code in a container, the following will work

InitialContext ctx = new InitialContext();