Developing a simple application from scratch to production using SpringBoot and Securing it

What we are going to do?

We will develop an  application using Java technologies which will work in all devices. We will start from the very beginning of Requirements Gathering and go through all the phases of Analysis, Design, Implementation and Deployment in a step by step manner.

Table of contents

  1. Introduction about application
    • High Level Requirements
  2. Requirement Analysis
  3. Setting up Development Environment
  4. Building App in sprints
    1. Sprint 1 – prepare of skeleton
    2. Sprint 2 – Configure Security
    3. Sprint 3 – Setup Email Service
    4. Sprint 4 – Setup Jenkins

PAN explained

PAN is a 10 digit alpha numeric number, where the first 5 characters are letters, the next 4 numbers and the last one a letter again. These 10 characters can be divided in five parts as can be seen below. The meaning of each number has been explained further.
1. First three characters are alphabetic series running from AAA to ZZZ
2. Fourth character of PAN represents the status of the PAN holder.
• C — Company
• P — Person
• H — HUF(Hindu Undivided Family)
• F — Firm
• A — Association of Persons (AOP)
• T — AOP (Trust)
• B — Body of Individuals (BOI)
• L — Local Authority
• J — Artificial Juridical Person
• G — Government
3. Fifth character represents first character of the PAN holder’s last name/surname.
4. Next four characters are sequential number running from 0001 to 9999.
5. Last character in the PAN is an alphabetic check digit.
Nowadays, the DOI (Date of Issue) of PAN card is mentioned at the right (vertical) hand side of the photo on the PAN card

Diffrerent Types of VISAs‏

Types of Visas
The Visa Section frequently issues the nonimmigrant visas shown in the lists below. To learn more about these types of visas or to see if they match your reason for seeking entry to the U.S., click on a title below.

Tourism, Business & Transit

B Visas: Temporary Visitors (Business/Pleasure/Medical)
C-1 Visa: Transit Aliens
C-1/D Visa: Alien Crewmember in Transit
I Visas: Information Media Representatives
Visa Waiver Program

F Visas: Academic Students
J Visas: Exchange Visitors
M Visas: Non-Academic Students
Temporary Work in the U.S.

H Visas: Temporary Workers & Trainees (H1B)
L Visas: Intra-Company Transferees
O Visas: Aliens with Extraordinary Ability
P Visas: Athletes, Artists & Entertainers
Q Visas: International Cultural Exchange Visitors
B Visas: Domestic Employees
Diplomats & Officials

A Visas: Officials in Foreign Governments
C-2 & C-3 Visas: Diplomats & Officials in Transit
G Visas: International Organization Aliens

R Visas: Aliens in Religious Occupations
K Visas (Spouse, Fiancé(e) & Child(ren) of U.S. Citizen)
V Visas (Certain Spouses & Children of LPRs)

US Visas? Two basic types of US visas:

1. Immigrant visas: For those intending to reside permanently in the United States. (Whether or not they intend to work.)

2. Nonimmigrant visas: Visa for visiting United States temporarily. Tourist or medical treatment,businsess purpose,Students, Participants in exchange programs, Temporary workers, Performing artists, Professional journalists, and Government representatives, etc.

Different categories of visas:

Temporary Worker Visas:
There are several categories of temporary worker visas. All applicants for such visas, must have a petition approved by the U.S. Immigration and Naturalization Service (INS) before applying for the visa.

Registered nurses, persons in a speciality occupation H-1B, temporary or seasonal agricultural workers, temporary or seasonal non agricultural workers, trainees other than medical or academic, practical training in the education of handicapped children.

L Visa– Intra company transferees. L2 is a depdent visa for L1 family members.

O-1 Visa– Persons with extraordinary ability in the science, arts, education, business, athletics, or extraordinary achievements in the motion picture and television field.

P-1 to P-3 Visa– Individual or team of athletes, or members of an entertainment group, that are internationally recognized.

The spouse and unmarried, minor children of an applicant for H or L visas may also be classified as nonimmigrant in order to accompany or join the principal applicant.

** A person who has received a H4 visa as the spouse or child of a temporary worker, may not accept employment in the United States.

Student Visas:
There are two nonimmigrant visa categories for persons wishing to study in the United States. The F visa is for academic studies, and the M visa is for nonacademic or vocational studies.

** A spouse, and unmarried, minor children may also receive nonimmigrant visas to accompany or follow the student.


Visitors Visas( B1/ B2):
Visitors visas are nonimmigrant visas, for persons desiring to enter the United States temporarily for

Business purpose B1
For pleasure or Tourist purpose B2 visa.
For Medical treatment (B-2). (These visas are for a specifically limited period.)
Process to apply ?

All US visa applicants require to be interviewed by a US Consulate, before being granted a visa. Applicant need to appear in person for the Interview at consulate. A prior appointment is must for this purpose.

Find out which Consulate is applicable for you. There are 4 USA consulate in India and based on your address of residency/state in India, need to contact a specific service provider for that consulate that is applicable for you.

Prepare all the documents as per the list given above.
Setup an appoinment for the interview. Submit the documents.
Go for the interview on scheduled time, if visa approved give electronic fingure printing.
Passport will be delivered by courier at your address.

Change the IE Browser Title‏

Change the Browser Title

This tweak Customize the Title of the Internet Explorer.

1. Click Start > Run > Type gpedit.msc
2. Click User Configuration > Windows Setting > Internet Explorer
Maintenance > Browser User Interface
3. Double click on Browser Title
4. Click on Customize Title Bars
5. type in whatever you want
6. Click OK

Now you changed the title of your browser and you sure see what you
wrote when you open a New Window.

How to share internet connection using WINXP‏

How to share internet connection using WINXP

How to use Internet Connection Sharing
To use Internet Connection Sharing to share your Internet connection,
the host computer must have one network adapter that is configured to
connect to the internal network, and one network adapter or modem that
is configured to connect to the Internet.

On the host computer, follow these steps to share the Internet

1. Log on to the host computer as Administrator or as Owner.
2. Click Start, and then click Control Panel.
3. Click Network and Internet Connections.
4. Click Network Connections.
5. Right-click the connection that you use to connect to the Internet.
For example, if you connect to the Internet by using a modem,
right-click the connection that you want under Dial-up.
6. Click Properties.
7. Click the Advanced tab.
8. Under Internet Connection Sharing, select the Allow other network
users to connect through this computer’s Internet connection check box.
9. If you are sharing a dial-up Internet connection, select the
Establish a dial-up connection whenever a computer on my network
attempts to access the Internet check box if you want to permit your
computer to automatically connect to the Internet.
10. Click OK. You receive the following message:
When Internet Connection Sharing is enabled, your LAN adapter will be
set to use IP
address Your computer may lose connectivity with other
computers on
your network. If these other computers have static IP addresses, it is a
good idea to set them
to obtain their IP addresses automatically. Are you sure you want to
enable Internet
Connection Sharing?
11. Click Yes.
The connection to the Internet is shared to other computers on the local
area network (LAN). The network adapter that is connected to the LAN is
configured with a static IP address of and a subnet mask of

On the client computer
To connect to the Internet by using the shared connection, you must
confirm the LAN adapter IP configuration, and then configure the client
computer. To confirm the LAN adapter IP configuration, follow these
steps: 1. Log on to the client computer as Administrator or as Owner.
2. Click Start, and then click Control Panel.
3. Click Network and Internet Connections.
4. Click Network Connections.
5. Right-click Local Area Connection, and then click Properties.
6. Click the General tab, click Internet Protocol (TCP/IP) in the This
connection uses the following items list, and then click Properties.
7. In the Internet Protocol (TCP/IP) Properties dialog box, click Obtain
an IP address automatically (if it is not already selected), and then
click OK.

Note You can also assign a unique static IP address in the range of to For example, you can assign the following
static IP address, subnet mask, and default gateway: IP Address
Subnet mask
Default gateway

To configure the client computer to use the shared Internet connection,
follow these steps:1. Click Start, and then click Control Panel.
2. Click Network and Internet Connections.
3. Click Internet Options.
4. In the Internet Properties dialog box, click the Connections tab.
5. Click the Setup button.

The New Connection Wizard starts.
6. On the Welcome to the New Connection Wizard page, click Next.
7. Click Connect to the Internet, and then click Next.
8. Click Set up my connection manually, and then click Next.
9. Click Connect using a broadband connection that is always on, and
then click Next.
10. On the Completing the New Connection Wizard page, click Finish.
11. Quit Control Panel.
When you now start Microsoft Internet Explorer, the client computer will
try to connect to the Internet by using the host computer’s shared
Internet connection

Clean the virtual memory page files in Windows XP‏

How to clean the virtual memory page files in Windows XP

Virtual memory is a system enhancing functionality implemented for
Microsoft Windows operating systems. When you have multiple programs or
tasks running at the same time, Windows creates one or more virtual
memory pagefiles that store information not used by your memory (RAM).
These page files can sometimes contain sensitive information such as
credit-card numbers and passwords you enter

How to clean the virtual memory pagefiles

You can make your computer automatically clear the virtual memory
pagefiles whenever you shut down your computer. To do this, follow the
steps below:

1. Click Start, then click Run…

2. Type “regedit” then click OK. The Registry Editor will be displayed.

3. In the left menu, expand the following registry keys in this order:

HKEY_LOCAL_MACHINE, SYSTEM, CurrentControlSet, Control, Session Manager

4. Click the Memory Management folder,

5. In the right pane, double-click ClearPageFileAtShutdown. The Edit
DWORD Value window will be displayed.

6. Type 1 in the Value data field, then click OK.

7. Exit the Registry Editor.
8. Restart your system so the changes can take affect.

Type’s of Pc’s……….

Types of PC’s

There are a lot of terms used to describe computers. Most of these words
imply the size, expected use or capability of the computer. While the
term computer can apply to virtually any device that has a
microprocessor in it, most people think of a computer as a device that
receives input from the user through a mouse or keyboard, processes it
in some fashion and displays the result on a screen.

PC – The personal computer (PC) defines a computer designed for
general use by a single person. While a Mac is a PC, most people relate
the term with systems that run the Windows operating system. PCs were
first known as microcomputers because they were a complete computer but
built on a smaller scale than the huge systems in use by most

Desktop – A PC that is not designed for portability. The expectation
with desktop systems are that you will set the computer up in a
permanent location. Most desktops offer more power, storage and
versatility for less cost than their portable brethren.

Laptop – Also called notebookslaptops are portable computers that
integrate the display, keyboard, a pointing device or trackball,
processor, memory and hard drive all in a battery-operated package
slightly larger than an average hardcover book.

Palmtop– More commonly known as Personal Digital Assistants (PDAs),
palmtops are tightly integrated computers that often use flash memory
instead of a hard drive for storage. These computers usually do not have
keyboards but rely on touchscreen technology for user input. Palmtops
are typically smaller than a paperback novel, very lightweight with a
reasonable battery life. A slightly larger and heavier version of the
palmtop is the handheld computer.

Workstation – A desktop computer that has a more powerful processor,
additional memory and enhanced capabilities for performing a special
group of task, such as 3D Graphics or game development.

Server – A computer that has been optimized to provide services to
other computers over a network. Servers usually have powerful
processors, lots of memory and large hard drives.

Mainframe – In the early days of computing, mainframes were huge
computers that could fill an entire room or even a whole floor! As the
size of computers has diminished while the power has increased, the term
mainframe has fallen out of use in favor of enterprise server. You’ll
still hear the term used, particularly in large companies to describe
the huge machines processing millions of transactions every day.

Minicomputer – Another term rarely used anymore, minicomputers fall in
between microcomputers (PCs) and mainframes (enterprise servers).
Minicomputers are normally referred to as mid-range servers now.

Supercomputer – This type of computer usually costs hundreds of
thousands or even millions of dollars. Although some supercomputers are
single computer systems, most are comprised of multiple high performance
computers working in parallel as a single system. The best known
supercomputers are built by Cray Supercomputers.

Wearable – The latest trend in computing is wearable computers.
Essentially, common computer applications (e-mail, database, multimedia,
calendar/scheduler) are integrated into watches, cell phones, visors and
even clothing!