DEV Community: Ligouri S Tittus

#programming #java #beginners #webdev #computerscience

Ligouri S Tittus — Thu, 26 Feb 2026 15:01:18 +0000

Java (Programming language):

Ligouri S Tittus ・ Feb 26

#codenewbie #java #programming #payilagam

Java and PostgreSql Series :

Ligouri S Tittus — Thu, 26 Feb 2026 14:56:38 +0000

Now i'm going to learn about basic of java and postgresql with the real time examples not just me we are going to learn about the basics and we are going to workout on the programs with certain examples.
Updating new topics day by day.

In this series we are going to cover :

JAVA:

       Programming langauge

PostgreSql:

Java (Programming language):

Ligouri S Tittus — Thu, 26 Feb 2026 06:01:14 +0000

🌍 Why Do We Need Language?

How animals and humans even plants needs to communicate to fulfill their needs so they uses LANGUAGE.This is the same concept for programming language also where in the real life we uses voices as a medium but in the programming language we are going to use the computer as a medium .💻 Computers don’t understand human language.
They only understand machine language (0s and 1s).

Real time examples :
🤝 Human to Human Communication (Same Language)

HUMAN(english) ------> HUMAN(english) {DON'T need a translator}
[same language]
|
|

COMPUTER(binary) ------> COMPUTER(binary) {DON'T need a translator}
[same language]
|
|
JAVA PROGRAM -----> JAVA COMPILER {DON'T need a translator}
[Same Language]

BINARY--->(0&1) computer just understand 0's and 1's only.

🌐 Human to Human Communication (Different Language – Needs Translator)
HUMAN(english) ------> HUMAN(french) {Needs a translator}
[different language]
|
|
💻 Human to Computer Communication
HUMAN(english) ------> COMPUTER(binary) {Needs a translator}
[different language]
|
|
JAVA PROGRAM -----> Computer (Machine Code)
[Different Language → Needs Compiler]

🏗️ Two Types of Programming Languages

Low level language
High level language

1)Low level language:

👉 A language that is close to the computer hardware
👉 Computer understands it directly or almost directly

Types of Low-Level Languages:

Machine Language (Binary – 0 & 1)
Assembly Language

🔹 Features of Low-Level Language

Very fast execution
Direct hardware control
Hard to write and understand
Machine dependent
Less portable

2)High level language:

👉 A language that is close to human language
👉 Easy for humans to read and write

Examples:

Java
Python
C++

🔹 Features of High-Level Language

Easy to learn ✅
English-like syntax ✅
Portable (Write once, run anywhere – Java) ✅
Needs compiler/interpreter ❗
Slower than low-level (slightly)

This is enough for the beginners next we move to the programming language topics based on JAVA and later we can compare with other languages. Why we move 📜 From Plankalkül to Java?.

Answer if you know :

1️⃣ Why do computers need programming languages if they only understand binary (0s and 1s)?
2️⃣ What is the role of a compiler in communication between a Java program and a computer?
3️⃣ What is the difference between same-language communication and different-language communication in programming?
4️⃣ What are the key differences between low-level language and high-level language?
5️⃣ Why did programming languages evolve from early languages like Plankalkül to modern languages like Java?

Java Script (intro)

Ligouri S Tittus — Tue, 14 Oct 2025 07:42:47 +0000

**1. Histroy of JS

What is java script?
Why we need JS?
How the JS works?
Where we use JS?**

1] History of js:

JavaScript was created in 1995 by Brendan Eich, while he was at Netscape.
Its original name was Mocha, then LiveScript, before being renamed JavaScript.
Microsoft released its own version, called JScript, with Internet Explorer 3.
In 1997, Netscape submitted JavaScript to ECMA International for standardization, which led to the first edition of the ECMAScript standard.
ECMAScript 3 was a significant update, and there was a planned Edition 4 which was eventually abandoned. Some parts of what was intended in Edition 4 were later folded into ES5.
**
2]What is Java Script?**
JavaScript is a cross-platform, object-oriented scripting language used to make webpages interactive (e.g., having complex animations, clickable buttons, popup menus, etc.). There are also more advanced server side versions of JavaScript such as Node.js, which allow you to add more functionality to a website than downloading files (such as realtime collaboration between multiple computers). Inside a host environment (for example, a web browser), JavaScript can be connected to the objects of its environment to provide programmatic control over them.
Object-oriented. No distinction between types of objects. Inheritance is through the prototype mechanism, and properties and methods can be added to any object dynamically.
-Variable data types are not declared (dynamic typing, loosely typed).

-Cannot automatically write to hard disk.

3]Why we need JS?

To Make Web Pages Interactive :

Without JS, web pages are static — they just display information.
JS makes them respond to users.
👉 Example: Buttons that show/hide content, image sliders, pop-ups, form validation.
**
To Handle Dynamic Content:**

JS allows content to change without reloading the page.
👉 Example: New tweets appearing on Twitter automatically.

To Validate Forms:

Before sending data to the server, JS checks user inputs.
👉 Example: Checking if an email is valid or a password is strong.

To Build Web Applications:

Modern apps like Gmail, YouTube, and Facebook are powered by JavaScript (and frameworks like React, Angular, or Vue).

To Communicate with Servers:

JS can fetch or send data from servers in the background using AJAX or Fetch API.
👉 Example: Loading comments on a post without refreshing.

For Game and App Development:

You can use JS to create games, mobile apps (with React Native), and even desktop apps (with Electron).

To Control Multimedia and Animations:

JS can play audio/video, animate elements, or create visual effects.

4] How js works?
JavaScript is the brain of a web page — it makes things happen (like clicking buttons, showing popups, or changing colors).

It mainly runs inside the browser (like Chrome, Firefox, Edge), and sometimes on servers (like with Node.js).

Browser loads the web page

When you open a web page:

The browser downloads the HTML file.
It reads the CSS file to style the page.
Then it finds any JavaScript (.js) files and starts executing them.

<script src="script.js"></script>

The engine:

Reads your JS code.
Converts it into something the computer understands.
Executes it line by line.

The browser:

JS Engine → Executes code → Interacts with DOM → Handles events → Updates the page dynamically

How the day goes beyond class in my own words.(Attract with blogs)

Ligouri S Tittus — Wed, 24 Sep 2025 15:47:16 +0000

Today we discussed about the topics are not just we learn in the regular classes (Trainee and we) thinks this will also helps after getting jobs.here are the topics

Blogs
Git
Online meetings

1.Blogs: (EXPERIENCED)
I came to know how the blog works on my day today life and improvement of my learning. Sorry not learning it's all about reading.

Learning means what we do just memorize the things that we have seen in the website or what tutor explained in the class.

But what we want to do means we have to (CROSS VERIFY) it seems to be a valid point. Because if we want to buy a new Laptop or Mobile means what we just do we just go to multiple websites to see which one is better comparatively.By learning me we should go through at least 2-3 websites.

LEARNING:
1)Spellings
2)How to form basic sentence
3)New words (with meanings)
4)New content (through multiple websites)
5)Typing make easier
we can explain with more but this will be enough.
**
2.Online meetings:(NOT EXPERIENCED)**
_ Why we want to attend the online meetings ?_

To get understanding with the seniors in the information technology team and and to clear doubts with them.
We have fear to talk in front of known and unknown peoples about the thins we have learnt. This will makes us to reduce the fear to speak infront of many knowledgeable peoples.
Raise questions where you have doubts or somethings you want to ask about related things.

3.Resume building:
Weekly update the resume that you learned things related to the industry.
Gothrough the resumes of others for improvement of the layout and things to be changed.
**
KANCHI LUG: Free meeting TAMIL
https://kanchilug.wordpress.com/

ILUGC: Free meeting ENGLISH
https://ilugc.in/**

Constructor &Types of constructor (with examples)

Ligouri S Tittus — Thu, 04 Sep 2025 15:01:28 +0000

What is constructor ?

In Java, a constructor is a special method used to initialize objects. Unlike regular methods, constructors are invoked when an instance of a class is created. They have the same name as the class and do not have a return type. Constructors are essential for setting initial values for object attributes and preparing the object for use.

Why Do We Need Constructors in Java ?

Constructors play a very important role, it ensures that an object is properly initialized before use.

What happens when we don't use constructors:

Without constructors:

Objects might have undefined or default values.
Extra initialization methods would be required.
Risk of improper object state

When Java Constructor is Called?

Each time an object is created using a new() keyword, at least one constructor (it could be the default constructor) is invoked to assign initial values to the data members of the same class.

Types of Constructors in Java

Default Constructor (No-Argument Constructor)
Parameterized Constructor
Copy Constructor

1. Default Constructor in Java(No-Argument Constructor)

A constructor that has no parameters is known as default constructor. A default constructor is invisible. And if we write a constructor with no arguments, the compiler does not create a default constructor. Once you define a constructor (with or without parameters), the compiler no longer provides the default constructor. Defining a parameterized constructor does not automatically create a no-argument constructor, we must explicitly define if needed.

For example:

import java.io.*;

// Driver class
class Geeks{

    // Default Constructor
    Geeks() { 
        System.out.println("Default constructor"); 

    }

    // Driver function
    public static void main(String[] args)
    {
        Geeks hello = new Geeks();
    }
}

2. Parameterized Constructor in Java

A constructor that has parameters is known as parameterized constructor. If we want to initialize fields of the class with our own values, then use a parameterized constructor.

import java.io.*;

class Geeks {

    // data members of the class
    String name;
    int id;

    Geeks(String name, int id) {
        this.name = name;
        this.id = id;
    }
}

class GFG 
{
    public static void main(String[] args)
    {
        // This would invoke the parameterized constructor
        Geeks geek1 = new Geeks("Sweta", 68);
        System.out.println("GeekName: " + geek1.name
                           + " and GeekId: " + geek1.id);
    }
}

Copy constructor (TBD)

Reference:https://www.geeksforgeeks.org/java/constructors-in-java/
https://www.datacamp.com/doc/java/constructors

Constructor in java

Ligouri S Tittus — Thu, 04 Sep 2025 04:12:54 +0000

*What is constructor ?
*
In Java, a constructor is a special method that is used to initialize objects when they are created.
The constructor is called when an object of a class is created.
A constructor in Java is similar to a method.
The Java compiler
provides a default
constructor if you don't
have any constructor in a
class.

Rules for creating Java constructor:
There are two rules defned for the constructor.

Constructor name must be the same as its class name
A Constructor must have no explicit return type

Types of Java constructors

There are two types of constructors in Java:

Default constructor (no-arg constructor)
Parameterized constructor

Example for constructor:

class Student {
    String name;
    int age;

    // parameterized constructor
    Student(String n, int a) {
        name = n;
        age = a;
    }
}

public class Main {
    public static void main(String[] args) {
        Student s1 = new Student("John", 20);
        System.out.println(s1.name + " " + s1.age);
    }
}

Polymorphism in java

Ligouri S Tittus — Tue, 02 Sep 2025 13:12:01 +0000

What is polymorphism?
The ability of something to exist or be treated in multiple ways depending on the context.

Polymorphism allows objects to behave differently based on their specific class type

"Poly" = many
"Morph" = forms Polymorphism - > Many forms

That means one thing can be used in different ways depending on the situation.

Why we need polymorphism?

Consider a scenario with different types of Shape objects (e.g., Circle, Rectangle). Without polymorphism, _one might need separate methods to draw _each shape: drawCircle(), drawRectangle(). Polymorphism allows for a single draw() method that behaves differently based on the specific Shape object.

// Parent class
class Shape {
    public void draw() {
        System.out.println("Drawing a generic shape.");
    }
}

// Subclass 1
class Circle extends Shape {

    public void draw() {
        System.out.println("Drawing a Circle.");
    }
}

// Subclass 2
class Rectangle extends Shape {

    public void draw() {
        System.out.println("Drawing a Rectangle.");
    }
}

public class PolymorphismExample {
    public static void main(String[] args) {
        Shape myCircle = new Circle();
        Shape myRectangle = new Rectangle();

        myCircle.draw();    // Calls Circle's draw() method
        myRectangle.draw(); // Calls Rectangle's draw() method
    }
}

In this example, myCircle and myRectangle are both declared as Shape type, but when draw() is called, the specific implementation from Circle or Rectangle is executed at runtime due to polymorphism (specifically, method overriding). This demonstrates how a single method call can exhibit different behaviors based on the object's actual type.

Types of Java Polymorphism

In Java Polymorphism is mainly divided into two types:

Compile-time Polymorphism(Method overloading)
Runtime Polymorphism(Method overriding)

1)Compile time polymorphism (method overloading):

Within a class one (or) more methods having same method names but different in parameters.
It can be differ in numbers of parameters and different in data types.
**
2)Run time polymorphism (method overriding):**
Method overriding is an example of runtime polymorphism. In method overriding, a subclass overrides a method with the same signature as that of in its superclass. During compile time, the check is made on the reference type. However, in the runtime, JVM figures out the object type and would run the method that belongs to that particular object.

Reference:https://www.w3schools.com/java/java_polymorphism.asp
https://www.google.com/search?client=ms-android-vivo-terr1-rso2&sca_esv=0cc3b5bc5eb43f9c&sxsrf=AE3TifPuN27XRV1kYEAGBphyaE2yqm_6BA:1756804100770&q=Why+we+need+polymorphism+in+java+with+example&sa=X&sqi=2&ved=2ahUKEwiA-Pai3bmPAxWnzDgGHdZGAbkQ1QJ6BQikARAB&biw=392&bih=751&dpr=2.75

Test and Report generation

Ligouri S Tittus — Sat, 30 Aug 2025 17:48:42 +0000

In today's class we had one test.
In this test we got the question form the jave until we learnt from the class.
And while conducting the test our mentor asked our students to come one by one and he said I will make a report about u from your blog,git and notes that we have taken .
In the test he asked about the topic

What is compiler and interpreter
Feature of java
What is class and objects.
What is Identifiers
Declaration and Initializtion
What is ASCII and UNICODE?
Program (Hierarchical Inheritance)

Form this question i managed to write about all the questions but not one question.
That is Different between ASCII and UNICODE .
I just learnt now

Inheritance

Ligouri S Tittus — Fri, 29 Aug 2025 15:29:16 +0000

Todays we discussed about inheritance.

One class(child class)gets the properties and behaviour (method)of the another class(Parent classes).

There 5 types of inheritance:

How it works diagram:

1. Single Inheritance → One class inherits from another.
Example:

2. Multilevel Inheritance → A class inherits from a class, which again inherits from another class (a chain).
Example:

3. Hierarchical Inheritance → Multiple classes inherit from the same parent class.
Example:

4.Multiple Inheritance (via Interfaces) → A class implements multiple interfaces (since Java doesn’t allow multiple inheritance with classes).

5. Hybrid Inheritance (via Interfaces) → Combination of two or more types of inheritance, achieved using interfaces.

Recive the topic untill...

Ligouri S Tittus — Thu, 28 Aug 2025 15:31:49 +0000

In today's class we just discussed about the topic untill we covered in java. And I just go through
Some topics in quantitive aptitude.
I have learnt about what is number system and how the architecture is .
In this number system I have learnt four topics.

How number system divides
Unit digit
Sum of series
Divisibility rules

1)How number system divides:

2) Divisibility rules:

3)Unit digits:

4) Sum of series:

Come accross the simple logic, tricks and simple formulas we can easily solve the following problems.

Parameters and return type

Ligouri S Tittus — Thu, 28 Aug 2025 15:11:42 +0000

What is parameters and how it declared?
Parameters are variables defined in the method declaration after the method name, inside the parentheses. This includes primitive types such as int, float, boolean, etc, and non-primitive or object types such as an array, String, etc.

Return type

In methods we can write only one return type because after returning the value wa can store only one variable.