J2EE Flow & Errors Clarification

[RaniThomas]

Hi,
Can anyone please help me..
Im doing a J2EE Project for my own understanding...
I have developed the JSP pages, Java-Servlets for
Login Page (Username Txt, Password Txt, Submit, Sign Up)
Registration Page(Required Fields with Submit)

No special logics are there, Just i want the following things to be implemented while clicking the submit button,

(1) All the profile stuff(username, pwd, firstname,age,phone....) will have to stored in the database(MySQL)

(2) After storage, it will have to redirected to success.jsp page which displays the message "Profile Successfully Created & Stored"

Now the problem is, no errors in my code, but when im trying to fill all the profile fields and while pressing submit button, the errors are coming like,

java.lang.NullPointerException
model.Validation.validate(Validation.java:9)
LoginServlet.doPost(LoginServlet.java:61)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

So now vat can i do.....
Please help me.... I have refer the peter_budo's sample project....
And wanna know the flow of the project....

[~s.o.s~]

IMO, the error is pretty obvious. What you need to do here is start small. Instead of getting an entire application to work, concentrate on miniscule exercises. Something like:
- Having only one text field on your page and displaying the value on STDOUT after the user presses submit
- Now validate the value and print appropriate message
- Insert the validated text in database

Read some good online books to get a grasp of how a JEE application is structured and how it all works. Explaning the *entire* application flow is something no one would be willing to do IMO...