errors while accessing MySQL database

[Robinson Francis]

Hello and Good day to every one,
I am trying to build a DB based application that will validate login ID of users. This project is part of tutorial that can be found here: http://met.guc.edu.eg/OnlineTutorials/JSP%20-%20Servlets/Full%20Login%20Example.aspx

The application will

Ask the user to input his "username" and "password"
Check the existence of this user in the Data Base
If exists, Retrieve his first name and last name from the DB and display them
If not registered, Display "Sorry, you are not registered".

The folder structure of the project can be referred from the Attachement. The Main class that handles connection to the database is the ConnectionManager. java . The code is as below.

package ExamplePackage;

import java.sql.*;
import java.util.*;

import javax.naming.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class ConnectionManager {
	
	static Connection con;
    static String url;
    
    public static Connection getConnection(){
    	String DATASOURCE_CONTEXT = "java:comp/env/jdbc/important_schema";
    	
    	Connection result = null;
    	try {
			//Initialize the Context
			Context initialContext = new InitialContext();//Create a pointer to the root of the JNDI tree.
			//Create a DataSource object
			DataSource ds = (DataSource)initialContext.lookup(DATASOURCE_CONTEXT);
			//Get connection object
			Connection con = ds.getConnection();
			
			
		} catch (RuntimeException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch(SQLException ex){
		     ex.printStackTrace();
	    }
    	
		
		return con;
    }
    

}

The settings for the datasource in my WeblOGic Server is shown in the attached picture.


When I try to run the project and key in the Username and password, I get an error as below.

>
Your user name is ROBINSON
Your password is FRANCIS
Query: SELECT * FROM users where username='ROBINSON' AND password='FRANCIS'
javax.naming.NameNotFoundException: While trying to look up comp/env/jdbc/important_schema in /app/webapp/LoginExample/4240780.; remaining name 'comp/env/jdbc/important_schema'
at weblogic.jndi.internal.BasicNamingNode.newNameNotFoundException(BasicNamingNode.java:1139)
at weblogic.jndi.internal.ApplicationNamingNode.lookup(ApplicationNamingNode.java:144)
at weblogic.jndi.internal.WLEventContextImpl.lookup(WLEventContextImpl.java:254)
at weblogic.jndi.internal.WLContextImpl.lookup(WLContextImpl.java:380)
at weblogic.jndi.factories.java.ReadOnlyContextWrapper.lookup(ReadOnlyContextWrapper.java:45)
at weblogic.jndi.internal.AbstractURLContext.lookup(AbstractURLContext.java:130)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at ExamplePackage.ConnectionManager.getConnection(ConnectionManager.java:25)
at ExamplePackage.UserDAO.login(UserDAO.java:30)
at ExamplePackage.LoginServlet.doGet(LoginServlet.java:34)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3498)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(Unknown Source)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2180)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2086)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1406)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
Log In failed: An Exception has occurred! java.lang.NullPointerException


Can you please help me on this? I was told that it has got to do with the way the jdbc datasource is named in the Weblogic console but I am not sure. Please help me on this. Thank you all in advance.