GMAIL SERVER ARCHITECHTURE

GMAIL SERVER ARCHITECHTURE TO UNDERSTAND BOTH CLIENT SYSTEM BROWSER AND SERVER SYSTEM

Let us understand the gmail server architecture in 12 steps of description

1. First you will open browser, then you enter gmail server address "gmail.com" in the address bar 
2. Soon you press "enter" key on keyboard, you will observe gmail login page is apeared. Is that logic page HTML code available in your computer? Or is it downloaded from gmail server? It is downloaded from general server then your browser renders that html code and displays it to you. now tell me HTML technology develops what type of application? Web supportive application 
3. Now, as per next step you will enter your gmail account username and password, and you will click "sign in" button. If the given username and password is correct you will get your inbox mails, else you will get an error page saying that username and password incorrect.
4. what happened in background? :    Browser sends the given username and password to gmail server. Gmail server reads these values and passes those values to an application runing on server side. It is nothing but servlet, means web application. 
5. Then servlet passes those values to database interaction application, JDBC program.
6. Now, JDBC program executes SELECT query on DB LOGIN table to check whether user exists with the given values or not. If user exists DB returns userid                                                The query would be                                                                                                                   SELECT userid FROM login WhERE uname=givenusername AND pwd=given
7. Using this returned userid, JDBC program executes another SELECT query on INBOX table to get all mails related to this user. DB sends all mails related to this user to JDBC application. The query would be                                                                                                                          SELECT mails FROM inbox WHERE userid= returnedid;
8. Then JDBC application sends those mails to Servlet.
9. Now the servlet sends those mails to jsp to format the mails with help of html hyperlinks 
10. Using these mails, JSP generates HTML code dynamically and sends that html code to servlet 
11. Servlet sends those mails which are formatted in html code to the browser 
12. Finally, the browser displays those mails to user.