Forem: MANIKANDAN

Day 1 of building my project from scratch.

MANIKANDAN — Sun, 05 Apr 2026 15:26:52 +0000

Hello all...💡

This blog is not just about learning something theoretical,
You would think what he is saying. Why am I saying not to learn theoretically? Because I am the real example for you
I have learned HTML, CSS, JavaScript, Java, and so on, but
I can't really do a project now, fully.

So I got an idea, why could I try to do a project from scratch, so that it could give me confidence that I have done something new, by which I could learn new concepts and use the concepts that I have learned theoretically

From today, I will post what and all I am doing to create this project. Still, I have not decided what project to do, okay
I will update you on what project I am going to do, and why I have chosen it

Seri friends, naalai paapom

The Hidden Life of JavaScript

MANIKANDAN — Tue, 20 Jan 2026 02:12:26 +0000

JavaScript is one of the most widely used programming languages today. Whether you are browsing social media, shopping online, or using a web app, JavaScript is likely working behind the scenes. But have you ever wondered how JavaScript actually runs?

We will explore:

What a JavaScript Engine is
How Does a JavaScript Engine Work

What is a JavaScript Engine?

A JavaScript engine is a specialised program that reads, understands, and executes JavaScript code. Think of it as the interpreter that takes the code you write and transforms it into actions your computer can perform.

Popular JavaScript engines include:

V8 (used in Google Chrome )
SpiderMonkey (used in Mozilla Firefox)
JavaScriptCore (used in Safari)

Each engine is unique in its implementation, but the core principles remain the same.

How Does a JavaScript Engine Work?

1. Parsing: Understanding the Code

The first step is parsing, where the engine converts JavaScript into an Abstract Syntax Tree (AST)— a structured representation it understands.

Think of this process as breaking the code into small, logical pieces to analyze its purpose. For example:

console.log("Hello bro");

The engine identifies this as a function call (console.log)with the argument "Hello bro".

2. Compilation: Preparing for Execution

Modern JavaScript engines use Just-In-Time (JIT) Compilation, converting JavaScript into machine code just before execution. This makes it run much faster than interpreting line by line.

3. Execution: Running the Code

Once compiled, the engine runs the machine code. For example, if your code includesconsole.log("Hello!"), it prints "Hello!" to the console.

Key Components of a JavaScript Engine

To perform these tasks, the engine relies on three main components:

1. Memory Heap

This is where data like variables, objects, and functions are stored. Think of it as a storage area where the engine keeps track of everything your code needs.

2. Call Stack

The call stack keeps track of what the engine is currently working on. When a function is called, it is added to the stack. Once the function finishes, it is removed from the stack.

3. Garbage Collector

As your program runs, some data is no longer needed. The garbage collector automatically clears this data from memory to keep things efficient and prevent your application from slowing down.

let user = {
  name: "Mani"
};

user = null; // object is no longer reachable

Main Garbage Collection Method: Mark and Sweep

This is how JavaScript engines work internally:

Start from root objects (global variables, current function variables)
Mark all reachable objects
Sweep (delete) all unmarked objects

Summary

A JavaScript engine is an incredible piece of technology that brings your code to life. It is built for speed and efficiency to parse, compile, and handle asynchronous tasks with the Event Loop.

Stop here. Come back tomorrow ....Hava a good day

The Silent Power Behind Every Success

MANIKANDAN — Sat, 03 Jan 2026 17:04:01 +0000

This year, we have to be disciplined if we really want to reach our goal. It is not easy, and it will not happen fast. Some days we will feel lazy, some days we will feel tired, and some days we will feel like skipping everything. But discipline means doing the work even on those days. Not extra work, just the small work that needs to be done daily.

The process will be slow, and many times we will not see any result. That is the hardest part. We wake up, do the same thing again and again, and feel like nothing is changing. But actually, something is changing inside us. Our habits are getting stronger, and we are becoming more serious about our goal, even if we don’t notice it immediately.

If we continue daily without checking the result every time, one day we will see it clearly. That day will feel very good. We will understand that all those small efforts were not wasted. Discipline may be boring sometimes, but it quietly takes us where we want to go.

5 Essential Array Methods Every JavaScript Developer Must Know

MANIKANDAN — Sat, 15 Nov 2025 06:12:58 +0000

What is a method?

A method is just a function inside an object,
and it represents what the object can do.

Now we are going to see some of the most frequently used built-in methods in JavaScript

Array methods()

1) push()

--> It is used to add one or more elements to the end of an array.
--> It also returns the new length of the array.

Syntax

array.push(element1, element2, ...);

Example

let tasks = ["Wake up", "Brush teeth"];

tasks.push("Exercise", "Read a book");

console.log(tasks);

Output

["Wake up", "Brush teeth", "Exercise", "Read a book"]

2) pop()

-->pop() removes the last element from the array
--> It returns the removed element

Syntax

array.pop();

Example

let tasks = ["Wake up", "Brush teeth", "Exercise", "Read a book"];

let removedTask = tasks.pop();

console.log(tasks);
console.log("Removed:", removedTask);

Output

["Wake up", "Brush teeth", "Exercise"]
Removed: Read a book

3) shift()

-->shift() removes the first element from the array
--> It returns the removed element

Syntax

array.shift();

Example

let tasks = ["Wake up", "Brush teeth", "Exercise", "Read a book"];

let removedTask = tasks.shift();

console.log(tasks);
console.log("Removed:", removedTask);

Output

["Brush teeth", "Exercise", "Read a book"]
Removed: Wake up

4) unshift()

-->unshift() adds one or more elements to the beginning of the array
--> It returns the new length of the array

Syntax

array.unshift();

Example

let tasks = ["Brush teeth", "Exercise", "Read a book"];

let newLength = tasks.unshift("Wake up");

console.log(tasks);
console.log("New Length:", newLength);

Output

["Wake up", "Brush teeth", "Exercise", "Read a book"]
New Length: 4

5) map()

--> map() creates a new array
--> It runs a function on every element of the original array
--> It does NOT change the original array

Syntax

array.map(function(element, index, array) {
// return new value
});

Example

let numbers = [1, 2, 3, 4];

let doubled = numbers.map(function(num) {
return num * 2;
});

console.log(numbers);
console.log(doubled);

Output

[1, 2, 3, 4]
[2, 4, 6, 8]

JDBC Connectivity in Java (Java Database Connectivity)

MANIKANDAN — Thu, 23 Oct 2025 16:11:29 +0000

What is JDBC?

JDBC (Java Database Connectivity) is a Java API that lets Java programs talk to databases. It provides classes and interfaces to send SQL queries, get results, and manage database connections. Using JDBC, we can build applications that work with different databases like MySQL, PostgreSQL, Oracle, and more. Basically, it helps Java programs store, read, and update data in a database easily.

The main 6 steps for connection of JDBC

                     Import packages
                           |
                      Load Driver  
                           |
                     Register Deiver
                           |
                   Create a connection
                           | 
                     Create Statement
                           |
                         Close

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

public class Crud_Op_Ps {

    public static void main(String[] args) {
        String url = "jdbc:postgresql://localhost:5432/crud_op";
        String user = "manikandan";
        String password = "tnlm@2004";

        try (Connection con = DriverManager.getConnection(url, user, password);//ip 
                Scanner sc = new Scanner(System.in)) {

            System.out.println("DB connected...");

            while (true) {
                System.out.println("\n--- CRUD Menu ---");
                System.out.println("1. Insert User");
                System.out.println("2. Update User");
                System.out.println("3. Delete User");
                System.out.println("4. View Users");
                System.out.println("5. Exit");
                System.out.print("Enter your choice: ");
                int choice = sc.nextInt();
                sc.nextLine();

                switch (choice) {
                case 1:
                    System.out.print("Enter name: ");
                    String name = sc.nextLine();
                    System.out.print("Enter email: ");
                    String email = sc.nextLine();

                    String insert = "INSERT INTO student(name, email) VALUES (?, ?)";
                    try (PreparedStatement ps = con.prepareStatement(insert)) {       //ip
                        ps.setString(1, name);
                        ps.setString(2, email);
                        ps.executeUpdate();
                        System.out.println("User inserted.");
                    }
                    break;

                case 2:
                    System.out.print("Enter old name: ");
                    String oldName = sc.nextLine();
                    System.out.print("Enter new name: ");
                    String newName = sc.nextLine();

                    String update = "UPDATE student SET name=? WHERE name=?";
                    try (PreparedStatement ps = con.--prepareStatement(update)) {//ip
                        ps.setString(1, newName);
                        ps.setString(2, oldName);
                        int rows = ps.executeUpdate();
                        if (rows > 0) {
                            System.out.println("User updated.");
                        } else {
                            System.out.println("No user found with that name.");
                        }
                    }

Differences between abstract class and interface in Java

MANIKANDAN — Wed, 22 Oct 2025 16:25:20 +0000

What is an Abstract Class?

Abstraction in Java is the process of hiding internal implementation details and showing only essential functionality to the user. It focuses on what an object does rather than how it does it.

What is an Interface?
Java interface is a reference type in Java, similar to a class, that is used to achieve abstraction and multiple inheritance. It defines a set of abstract methods that a class must implement. Interfaces specify what a class must do, but not how it does it. This makes code more modular, flexible, and easier to manage, especially in large applications.


--------------------------------------------------------------
|  Abstract Class             |       Interface              | 
--------------------------------------------------------------
|  Abstract keyword used to   | Interface keyword used to    |
|  declare the abstract class.| declare interface. Also,     |
|  Also, the abstract class   | interface can be implemented |
|  can be extended by using   | by using the keyword         |
|  the keyword “extends”      | “implements”                 |     
|------------------------------------------------------------|
|  Can have access modifier   |  Does not have access        |
|                             |  modifiers, and everything   |
|                             |  defined inside is assumed   |
|                             |  to be a public modifier     |
|-----------------------------|------------------------------|
| Can declare constructors    | Cannot declare constructors  |
| and destructors             | or destructors               |
|------------------------------------------------------------|
| Can have data fields        | Cannot have data fields      |
|-----------------------------|------------------------------|
| Can have any type of class  | Can only have public members,|
| member (e.g., public,       | by default                   |
| private, protected)         |                              |
|-----------------------------|------------------------------|
| Can have only one abstract  | Can implement several        |
| class                       |                              |
--------------------------------------------------------------

Why HTML is a platform-independent language

MANIKANDAN — Wed, 08 Oct 2025 06:47:25 +0000

HTML, which stands for HyperText Markup Language, is a platform-independent language for several reasons:

Plain text files:
HTML is just a text file with tags. You can create or edit it on any computer—Windows, Mac, or Linux—using any text editor.

Browsers do the work:
Web browsers (Chrome, Firefox, Safari, etc.) read and display HTML. They work the same way on all operating systems, so your web page looks consistent everywhere.

No compilation needed:
HTML is not a programming language. Browsers read it directly, so you don’t need any special compiler for different platforms.

Standards make it uniform:
Organizations like W3C make rules for HTML. These rules ensure that browsers interpret HTML the same way, no matter the device or OS.

Responsive design:
HTML works with techniques that let websites adjust to any screen size—desktop, tablet, or phone—giving a smooth experience everywhere.

In summary, HTML's platform independence is primarily due to its text-based structure, browser interpretation, lack of compilation requirements, adherence to standardised specifications, and support for responsive design practices, all of which enable consistent rendering of web content across different platforms and devices.

HTML FORMS INTRODUCTION

MANIKANDAN — Tue, 30 Sep 2025 07:29:56 +0000

We’ve all come across login pages, feedback forms, profile update pages, survey forms, booking or reservation forms, contact forms, and registration pages—right? These forms are everywhere on the web, and we interact with them almost daily.

But have you ever wondered what's behind the magic of these user-friendly input boxes?

Well, it's HTML—the real don behind all these cool web forms!

Whether you're filling in your username, writing a short bio, uploading a profile photo, selecting options with checkboxes or radio buttons, choosing from a dropdown, or clicking a button to submit—HTML provides the skeleton for it all.

To create forms like these, we use the (form) tag in HTML.
Inside it, we'll define various other tags to bring everything together—text fields, checkboxes, buttons, and more.

What are all the major changes in HTML 1 to the current HTML 5?

MANIKANDAN — Mon, 29 Sep 2025 11:45:03 +0000

HTML:

HTML (Hypertext Markup Language) has evolved over the years, from its initial release as HTML 1.0 to its latest version, HTML 5.0. Let’s explore the key features and changes introduced in each version:

HTML 1.0 (1991):

It is the basic version of HTML with text, links,
paragraph, and lists
In this version, we can not add images, forms, or
styling feature

HTML 2.0 (1995):

Major change: Added forms, input, button, and table made website interactive(like data submission)
The concept of forms was introduced for user input and interaction with webpages.

HTML 3.2 (1997):

Enhanced support for tables, forms, and text formatting.
Introduction of new elements like image maps, applets, and
basic support for style sheets.

HTML 4.01 (1999):

In this version, div and span are used to separate
content and make the presentation easy
Expanded support for style sheets and scripting through
CSS (Cascading Style Sheets) and JavaScript.

HTML 5 (2014):

Major change, huge updates
semantic tags:-header, footer, article, section,nav
Multimedia tag:-video,audio

*BASIC-->INTERACTIVE-->STYLED-->SEMATIC-->MULTIMEDIA--CURRENT VERSION *

A new lesson from my recent interview experience

MANIKANDAN — Wed, 24 Sep 2025 18:54:17 +0000

A little introduction about me

Hey everyone! I am Manikandan, currently doing a Java full-stack course. I recently appeared for a Capgemini interview
for a production engineer and wanted to share my experience, the questions I faced, and how the process went for me. If you’re preparing for Capgemini or any other MNC company, this might help!

Application Process
I applied through the Superset application portal in August and received an online assessment on September 9.

The online Assessment
The online Assessment consists of three rounds

-> Round 1(SVAR – English Communication Test written)
-> Round 2(SVAR – English Communication Test speaking)
-> Round 3(Technical HR )

Round 1

The first round is all about your English grammar and
reading a paragraph and answering the question, The time
Given for this round is half an hour

From my own experience, learning English will not come
One day before the interview, you have to practice daily for it (like consistency is the key to success)

Round 2
This round was assigned after three days of the first round, so I thought I had failed in the first round. This is normal
Every human thought will be like this

The second round is speaking, which is divided into three
part

-> First, the AI will play an audio sentence, and we have to
lesson and repeat it by recording

-> Now again grammar came inside, the AI will play an audio
With some missing words, we have to fill in the missing
words with correct grammar and record the audio

-> The last part, they will give a scenario that we have to
continue it for 120 seconds, for me they gave imagine
Now you are in a crowded bus, and we have to continue
for 120s

NOTE:- for recording, there will be a certain timing, and you can not replay the audio again. We can play once

Round 3

Round three is the technical interview online. I was terrified in this round because this is my first one-to-one interview, and I have overcome the fear and attended the interview with full confidence

The first question from the hr is Tell me about yourself
And I told my intro that I am a blog writer,
the hr told Super Super, and moved to the next question, what are all the subjects in your college? So I wrote a theory paper and programming languages like Python, Java, and C++

After that, the Hr asked, Do you know this much language ok, good. Which programming language are you good at? I told Java, so they asked a question from Java

Question 1
What are all the pillars of OOPS?

After I told her, she asked about inheritance. I know the

answer, but while saying the answer, I have told multiple

Inheritance is not possible in Java

Question 2
The next question was, you told Java does not support
Multiple inheritance, so tell me why it will not support

Question 3
What is a datatype?

Final Thoughts

After this round, I came to know that The hr is not asking questions on their own, they are asking questions based on what we are saying, so I learnt to be careful while answering. If you don't know what it is, don't give the hr an extra point to corner you, and I can't find it. I am saying the answer is correct or wrong because the face of the hr is always smiling. There is no reaction, all the above is my personal experience .

All the best for your next interview

Understanding HTML and CSS in a real project

MANIKANDAN — Tue, 23 Sep 2025 09:20:10 +0000

About the project
This is just a scratch portfolio website built using HTML and CSS(internal CSS only by using elements)

It contains a header and four sections on this webpage. Whenever we want to create a webpage, we have to decide
How can we break it into small blocks first, which will make it easier to add style to the element

*What is the use of this scratch webpage *

<html>
    <head>
        <title> MANIKANDAN T </title>


    </head>

    <body>
        <header>
            <h1> MANIKANDAN T</h1>

            <ul>
                <li><a href="abc">About me </a></li>
                <li><a href="abc">project</a></li>
                <li><a href="abc">content</a></li>
                <li><a href="abc">login page</a></li>

            </ul>
        </header>

        <section>
            <h1>About Me</h1>
            <p>Iam a web developer </p>
        </section>

         <section>
            <h1>Project</h1>
            <p> Library management </p>
            <p>Library management is a sub-discipline of institutional management that focuses on specific issues faced by libraries and library management professionals.</p>
        </section>

         <section>
            <h1>Content</h1>
            <p>About me </p>
        </section>

         <section>
            <h1>Login page</h1>
            <p>user login </p>
        </section>

        <style>
            header{

                border: 1px solid black;
                background-color: dimgrey;

            }

            a{
                text-decoration: none;
                color:black;

            }
            ul{
                list-style-type:none;
                display: flex;
                gap: 40px;

                justify-content: center;
                font-size:large;

            }
           header h1{
                text-align: center;
                color:white;
            }

            section{
                width:60%;
                margin:auto;
                margin-top: 10px;
                padding-left: 10px;
                background-color: bisque;
                 border-radius: 10px;
                /* border:1px solid black; */


            }
            body{

            }

        </style>

    </body>
</html>

From this webpage, I have learned some elements and styles like

--> <ul>
The

Note

--> a tag
The a HTML element (or anchor element), with its href attribute, creates a hyperlink to web pages, files, email addresses, locations in the same page, or anything else a URL can address

Note: when creating an anchor tag, it will be automatically
underlined in the text like

After using this CSS style, the anchor tag underline and
color of the anchor tag text is blue,for changing it we use
color style

--> h1
It is a heading tag , there are h1to h6 ,as the number

increase the size, reduce

Now you will have a doubt about why there is only 6 headings
tag, why not h7 because HTML has only six heading tags (h1 to h6) because a webpage doesn’t need more than six levels of titles, just like a book has a main title, chapters, and sub-sections. Search engines and screen readers also understand only these six levels. If you want a heading to look smaller or bigger than these, you simply use CSS to change the style instead of creating something like h7.

Output page

<p> Tag
A paragraph in HTML is simply a block of text enclosed within the

tag. The

tag helps divide content into manageable, readable sections. It’s the go-to element for wrapping text in a web page that is meant to be displayed as a distinct paragraph.

Syntax:<p> Some Content... </p>

The “final” Keyword in Java

MANIKANDAN — Tue, 16 Sep 2025 11:54:23 +0000

Overview

We will take a look at what the final keyword is, why it is used, where it is used and how to use it

Final
->In Java, the final keyword is used to denote constants. It can be used with variables, methods, and classes.

Using the final keyword in Java is like making a promise to yourself and other programmers that something won't be changed. You use it to enforce rules and prevent accidental modifications. It's all about making your code safer and more predictable.

The final keyword in Java is a non-access modifier used to prevent modification.

So, what is a non-access modifier?

Before going to that, we have to understand what an access modifier is

Access modifier
Access modifiers are like the locks on the doors. They control who can get inside and see what's there (public, private, protected ).

Non-access modifier
These are like special instructions or rules for how the house is built and how it behaves. They don't control who can enter, but they change the house's nature(Static, final)

Now you may wonder why you should use 'final'?

It is used to restrict the user from further modifying the entity to which it is applied. This keyword plays a crucial role in ensuring immutability and preventing inheritance or method overriding.

After knowing what and why the final is, you should know where to use it

We can use it in classmethodvariable

1) Final class

--->In Java, the final class cannot be inherited by another class. For example

final class FinalClass {
  public void display() {
    System.out.println("This is a final method.");
  }
}

// try to extend the final class
class Main extends FinalClass {
  public  void display() {
    System.out.println("The final method is overridden.");
  }

  public static void main(String[] args) {
    Main obj = new Main();
    obj.display();
  }
}

In the above example, we have created a final class named FinalClass. Here, we have tried to inherit the final class by the Main class.

When we run the program, we will get a compilation error with the following message.

cannot inherit from final FinalClass
class Main extends FinalClass {

2)final Method
In Java, the final method cannot be overridden by the child class. For example

class FinalDemo {

    public final void display() {
      System.out.println("This is a final method.");
    }
}

class Main extends FinalDemo {

  public final void display() {
    System.out.println("The final method is overridden.");
  }

  public static void main(String[] args) {
    Main obj = new Main();
    obj.display();
  }
}

In the above example, we have created a final method named display() inside the FinalDemo class. Here, the Main class inherits the FinalDemo class.

We have tried to override the final method in the Main class. When we run the program, we will get a compilation error with the following message.

display() in Main cannot override display() in FinalDemo
  public final void display() {
                    ^
  overridden method is final

3) final Variable

In Java, we cannot change the value of a final variable. For example

class Main {
  public static void main(String[] args) {


    final int AGE = 32;
    AGE = 45;
    System.out.println("Age: " + AGE);
  }
}

In the above program, we have created a final variable named age. And we have tried to change the value of the final variable.

When we run the program, we will get a compilation error with the following message.

cannot assign a value to final variable AGE
    AGE = 45;
    ^