General Tech Blog!

Difference between Web Server and Application Server

2009-11-08T22:47:00.000-08:00

Application server vs Web server

Web Server:

Handles only HTTP protocol
Consists of web container alone (Servlet/JSP)
Code has take care of security, transaction, database connectivity and messaging

Application Server:

Handles Multiple protocol
Contains web container + EJB container
Application server itself will take care of security, transaction, database connectivity, pooled data connections, data caches, session persistence, messaging and fail over protection

Explained more at
1) http://www.javaworld.com/javaqa/2002-08/01-qa-0823-appvswebserver.html?page=1
2) http://www.serverwatch.com/tutorials/article.php/10825_1355131_1/Web-Servers-vs-App-Servers-Choosing-Between-the-Two.htm

Difference Between JAR, WAR and EAR files

2009-11-08T18:34:00.000-08:00

All these JAR, WAR and EAR files can be created using JAR tool.

JAR (Java ARchive) contains

Library Class files
Resource files
Property files

WAR (Web ARchive) contains

JAR files (lib)
Java Class files (classes)
JSP, HTML, JS, CSS and image files
Deployment Descriptor (web.xml) and other configuration XML files

It is also called as Web Module.

EAR (Enterprise ARchive) contains

WAR files
JAR files
Enterprise Java Beans
Application Deployment Descriptor (application.xml) and other configuration XML files

EAR contains the complete enterprise application which consists of one or more web modules.

Note: Tomcat deals only with WAR files. If you want to install EAR files, use Apache Geronimo

For more details, refer http://www.javaworld.com/javaworld/jw-01-2008/jw-01-tomcat6.html?page=2

Sound problem with Ubuntu 9.04, kernel 2.6.28-13-generic Upgrade

2009-07-12T05:37:00.000-07:00

Recently, I upgraded my machine to Ubuntu 9.04, kernel 2.6.28-13-generic and had a problem with Sound driver(No Sounds at all). Solved by upgrading the ALSA to 1.0.20.

http://monespaceperso.org/blog-en/2009/05/09/upgrade-alsa-1020-on-ubuntu-jaunty-904/

Howto Install NetBeans IDE in Ubuntu 8.10

2009-05-18T17:59:00.000-07:00

The below article gives you the 2 possible ways of installing NetBeans in Ubuntu (Using Package Manager and Manual Install)

http://www.javadesign.info/SystemsHardware/OS/Ubuntu/install-netbeans-on-ubuntu

Which Language is best for writing Linux Distro's and Applications?

2009-05-17T20:31:00.000-07:00

The simple article from brighthub considers three popular programming languages C, Python and Java and discusses their own strength and weakness. Finally the author says that Java is the best choice.

Read out more @ http://www.brighthub.com/computing/linux/articles/34968.aspx

JChassis - Framework for small Java applications - Do simple things simply

2009-05-16T16:16:00.000-07:00

It is a framework for simple Java applications
The size of this framework is less than 100KB
It can run in Java runtime as well as J2ME Foundation Profile
It is NOT a web application framework

You can download it @ http://jchassis.sourceforge.net/

Wolfram Alpha - Computational Knowledge Engine - Screenshots

2009-05-16T12:42:00.000-07:00

Yesterday Wolfram|Aplha was released and I have tried some of the queries with it.
I tried some of the commons questions and here is the screen shots which I have tried

Some of the hits

Some of the misses

You can follow it in Twitter @ http://twitter.com/wolfram_alpha/

Do you want to know more about this? Check out the article in TechCrunch
http://www.techcrunch.com/2009/03/08/wolfram-alpha-computes-answers-to-factual-questions-this-is-going-to-be-big/

Moving Emails from One Account to Another

2009-05-08T19:14:00.000-07:00

Got from somebody as a forward. Hope this will help.

There can be several reasons why you may want to switch email service providers.

1. Reason #1. Your existing email address gets too much spam so you plan to dump the old account and switch to a new email address (a form of email bankruptcy).

2. Reason #2. You are leaving your existing job for higher studies and need to transfer all personal emails from the Microsoft Exchange server to your new university email account.

3. Reason #3. Your ISP’s email service isn’t reliable and you therefore plan to move to a free web based email service like Gmail, Yahoo Mail, Hotmail, etc.

4. Reason #4. You think the new email service from XYZ Inc. offers more features than your existing mail provider and hence want to make the move.

Here is a visualization which shows how to transfer email messages across the three most popular web email services. The transfer will happen online and you just need to specify the credentials (user name & password) of your old email account (from where you want to move message out) and your new email address (where you want to move messages in).

Moving to Windows Live Hotmail

Windows Live Hotmail is integrated with TrueSwitch so you can easily transfer emails from Yahoo Mail, AOL, Gmail, Live.com, .Mac, etc. to your shiny new Hotmail address. The same service may also be used for copying old email from an existing Hotmail account to a new Hotmail address.

Moving to Yahoo Mail

Like Windows Live Hotmail, Yahoo! Mail too provides integration with TrueSwitch so you can easy copy mails from Gmail, Hotmail, AOL, Juno, Rocket Mail, etc. into your Yahoo! account. With TrueSwitch, you can also copy mails from one Yahoo! inbox to another without upgrading to Yahoo! Mail Plus.

Moving to Gmail / Google Apps

Gmail (or Google Apps for Email) has a built-in Mail Fetcher feature that lets you download email messages from 5 different email accounts that support POP access. You may therefore use this feature to move your old Hotmail or AOL messages into Gmail as both these service provide free POP3 access.

The migration from Yahoo! Mail to Gmail is slightly tricky but possible.

Trick: Move emails from Yahoo Mail to Gmail or Outlook without POP

The free account of Yahoo Mail doesn’t provide IMAP or POP3 access so you can’t move these emails into Gmail or a desktop client like Microsoft Outlook.
The Yahoo! Mail Plus upgrade will add POP3 access to you account at $20 per year but if you want to same money, here’s a simple trick.

1. Create a new account at Windows Live Hotmail and fetch all your Yahoo! mails into this account using the free TrueSwitch Service.

2. Now that your mails are inside Hotmail, you can setup POP3 configuration to fetch those Yahoo messages into Gmail via Hotmail.

Migrating Emails Away from your ISP Account

TrueSwitch mentioned above supports all popular ISPs including Comcast, Verizon, CableVision, AT&T, etc. but if your ISP is not in the list and you don’t have the time to configure your email client for POP3 or IMAP access, check out Yippie Move.

It’s a online email transfer service similar to TrueSwitch but supports an even larger number of email service providers including the .edu addresses of certain colleges and universities in US. With YippieMove, you can choose folders (or labels in Gmail) that you want to copy to the new location without having to move the entire mailbox. The service is quick and easy but costs around $15 per email account.

Via Labanol

MVC Architecture (Model 2 Architecture)

2009-05-07T00:07:00.000-07:00

Most of us really good in MVC Patterns and concepts, but if you question them about the Model 1 and Model 2 Architecture, they are not sure with these names. Both MVC and Model 2 Architecture represents the same concepts whereas in Model 1 Architecture the Front Controller (Servlet) will not available.

The difference between these two Architectures are explianed in the below links.

http://www.javaworld.com/javaworld/jw-12-1999/jw-12-ssj-jspmvc.html
http://www.java-samples.com/showtutorial.php?tutorialid=350
http://www.comp.rgu.ac.uk/staff/rab/CM3028/Slides/model2-rab-student.ppt (Presentation)

Windows 7 (formerly known as Blackcomb and Vienna) Screenshots

2009-05-06T00:07:00.000-07:00

Windows 7 (formerly known as Blackcomb and Vienna) is the successor of Windows Vista. Windows 7 is expected to be released sometime in 2010.

Failed to allocate port(s) in the specified range for the following process(es): JMS 5540-5559,RMI 5520-5539,Database Control 5500-5519,EM agent 1830-

2009-05-05T23:53:00.000-07:00

Failed to allocate port(s) in the specified range for the following process(es): JMS 5540-5559,RMI 5520-5539,Database Control 5500-5519,EM agent 1830-1849

While installing oracle 10g with enterprise manager in Windows Vista home edition -32bit, If anyone of you got the above error while configuring EM through configuration assistant as well through emca (in command prompt), the reason is Windows Vista Edition Home will not support of installing Enterprise Servers.

The operating system should be of following edition to install Oracle 10g Enterprise Server.

· Business edition
· Enterprise Edition
· Ultimate Edition