Forem: Dev Ananth Arul

Java Features

Dev Ananth Arul — Thu, 16 Oct 2025 07:16:43 +0000

1) Simple Syntax:
Java is easy to learn to remove complex features like Pointers and multiple inheritane.
2)Object oriented:
Java is object oriented language.It supports core concepts of OOP like..
Class
Object
Inheritance
Encapsulation
Abstraction
Polymorphism
3)Platform indepedent:
Java is platform indepedent because of Java Virtual Machine(JVM).
when it write a java code is compiled to compilers to converting an byte code
4) Interpreted:
5) Scalable:
6) Portable:
7) Secure and Rebust:
8) Memory Management:
Memory management in java is automatically handled an Java Virtual Machine(JVM).
9) High performance:
10) Multiple threading:
Java allows multiple threads to allow run at an same time.
11) Rich Standard Library:
12) Functional Program features:
13) Integration with other Technologies:
14) Support for mobile and web application:
15) Documentation and community support:

Java Architecture

Dev Ananth Arul — Wed, 15 Oct 2025 17:44:04 +0000

Java architecture refers to the framework of components (Java Virtual Machine, Java Runtime Environment, and Java Development Kit) that enables Java programs to run on any device or platform, a concept known as "Write Once, Run Anywhere". The process involves the Java compiler converting source code into platform-independent bytecode, which the JVM then interprets and executes as machine-specific code.

Process of Java Architecture:

Writing Code: Developers write Java source code in java files.
**Compilation: **The Java compiler (part of the JDK) converts java files into platform-independent bytecode (saved as class files).
Execution: The JVM then takes this bytecode and converts it into machine code. which the underlying operating system can execute

Java Class, Object and Variables

Dev Ananth Arul — Tue, 14 Oct 2025 17:33:59 +0000

Java Classes:
In Java, a class serves as a blueprint or a template for creating objects. It is a fundamental concept in object-oriented programming (OOP) and defines the structure and behavior that objects of that class will possess.

A class is a template to create objects having similar properties and behavior, or in other words, we can say that a class is a blueprint for objects.
Properties of Java Classes:

Class is not a real-world entity. It is just a template or blueprint, or a prototype from which objects are created.
A class itself does not occupy memory for its attributes and methods until an object is instantiated.
A Class in Java can contain Data members, methods, a Constructor, Nested classes, and interfaces.

Java Objects:

Objects are the instances of a class that are created to use the attributes and methods of a class. A typical Java program creates many objects, which as you know, interact by invoking methods. An object consists of:

State: It is represented by attributes of an object. It also reflects the properties of an object.
Behavior: It is represented by the methods of an object. It also reflects the response of an object with other objects.
Identity: It gives a unique name to an object and enables one object to interact with other objects.

Java Variables:

In Java, variables are containers used to store data in memory. Variables define how data is stored, accessed, and manipulated.

A variable in Java has three components,

Data Type: Defines the kind of data stored (e.g., int, String, float).
Variable Name: A unique identifier following Java naming rules.
Value: The actual data assigned to the variable.

Rules to Name Java Variables:

Start with a Letter, $, or _ – Variable names must begin with a letter (a–z, A–Z), dollar sign $, or underscore _.
No Keywords: Reserved Java keywords (e.g., int, class, if) cannot be used as variable names.
Case Sensitive: age and Age are treated as different variables.
Use Letters, Digits, $, or _ : After the first character, you can use letters, digits (0–9), $, or _.
Meaningful Names: Choose descriptive names that reflect the purpose of the variable (e.g., studentName instead of s).
No Spaces: Variable names cannot contain spaces.
Follow Naming Conventions: Typically, use camelCase for variable names in Java (e.g., totalMarks).

Java Data Types

Dev Ananth Arul — Tue, 14 Oct 2025 17:18:30 +0000

Java is statically typed programming language which means variable types are known at the compile time.

In Java, compiler knows exactly what types each variable holds and enforces correct usage during compilation. For example "int x = "GfG";" gives compiler error in Java as we are trying to store string in an integer type.
Data types in Java are of different sizes and values that can be stored in a variable that is made as per convenience and circumstances to handle different scenarios or data requirements.
Java Data Type Categories:

Primitive Data Type: These are the basic building blocks that store simple values directly in memory. Examples of primitive data types are boolean, char, byte, short, int, long, float and double.

2.Non-Primitive Data Types (Object Types): These are reference types that store memory addresses of objects. Examples of Non-primitive data types are String, Array, Class, Interface and Object.

Java Introduction

Dev Ananth Arul — Mon, 13 Oct 2025 17:06:17 +0000

What is Java:
Java was introduced by James Gosling.Java is a high-level, object-oriented programming language developed by Sun Microsystems (now owned by Oracle) and released in 1995. It is known for its "write once, run anywhere" capability, meaning compiled Java code can run on any device or operating system that supports the Java Virtual Machine (JVM) without needing recompilation.

Features of java:

Object-Oriented Programming (OOP): Java supports OOP concepts to create modular and reusable code.
Platform Independence: Java programs can run on any operating system with a JVM.
Robust and Secure:Java ensures reliability and security through strong memory management and exception handling.
Multithreading and Concurrency:Java allows concurrent execution of multiple tasks for efficiency.
Rich API and Standard Libraries: Java provides extensive built-in libraries for various programming needs.
Frameworks for Enterprise and Web Development:Java supports frameworks that simplify enterprise and web application development.
Open-Source Libraries:Java has a wide range of libraries to extend functionality and speed up development.
Maintainability and Scalability:Java’s structured design allows easy maintenance and growth of applications.
Example:

// A Java program to print Hello World! public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } }

How to run the above code?

Write code in a file like HelloWorld.java.

The Java Compiler "javac" compiles it into bytecode "HelloWorld.class".

The JVM (Java Virtual Machine) reads the .class file and interprets the bytecode.

JVM converts bytecode to machine readable code i.e. "binary" (001001010) and then execute the program.

Java Introduction

Dev Ananth Arul — Mon, 13 Oct 2025 17:00:28 +0000

Features of java:

**Object-Oriented Programming (OOP): **Java supports OOP concepts to create modular and reusable code.

** Platform Independence:** Java programs can run on any operating system with a JVM.
Robust and Secure: Java ensures reliability and security through strong memory management and exception handling.
** Multithreading and Concurrency:** Java allows concurrent execution of multiple tasks for efficiency.
Rich API and Standard Libraries: Java provides extensive built-in libraries for various programming needs.
** Frameworks for Enterprise and Web Development:** Java supports frameworks that simplify enterprise and web application development.
Open-Source Libraries: Java has a wide range of libraries to extend functionality and speed up development.
** Maintainability and Scalability:** Java’s structured design allows easy maintenance and growth of applications.
Example:
// A Java program to print Hello World! public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } }

**
How to run the above code?**

Write code in a file like HelloWorld.java.
The Java Compiler "javac" compiles it into bytecode "HelloWorld.class".
The JVM (Java Virtual Machine) reads the .class file and interprets the bytecode.
JVM converts bytecode to machine readable code i.e. "binary" (001001010) and then execute the program.

Understanding React JSX Expressions and Attributes

Dev Ananth Arul — Wed, 01 Oct 2025 17:50:14 +0000

React JSX Expressions:
You can insert any valid JavaScript expression inside JSX by wrapping it in curly braces { }.

React will evaluate the expression and render the result in the DOM.

function Car() {
  return (
    <>
      <h1>My car</h1>
      <p>It has {218 * 1.36} horsepower</p>
    </>
  );
}

React JSX Attributes:
The class attribute is a much used attribute in HTML, but since JSX is rendered as JavaScript, and the class keyword is a reserved word in JavaScript, you are not allowed to use it in JSX.

JSX solved this by using className instead. When JSX is rendered, it translates className attributes into class attributes.

function Car() {
  return (
    <h1 className="myclass">Hello World</h1>
  );
}

Understanding React.js, JavaScript and JSX

Dev Ananth Arul — Thu, 11 Sep 2025 07:31:54 +0000

React.js:
React is is a open source library developed by Facebook (meta).
It is used for building user interface (UI), especially with single page Applications (SPA). React is a component based library, when UI is broken down into reusable building blocks. It is uses for virtual Dom like faster rendering and better performance.

Javascript:
JavaScript is a programming language used for web development to add interactivity,logic and functionality.It works in browsers(Servers like Node.js).
Syntax. Pure Java Script follows by ECMAScript (E36+) Standards.

JSX (JavaScript XML):
JSX is a syntax extension for JavaScript used with react compiled with Syntax HTML tags inside the JavaScript code. It works with HTML for JavaScript used tools for Babel in UI Structure in react.
JSX allows us to write HTML elements in JavaScript and place them in the DOM without any createElement() and/or appendChild() methods.
JSX converts HTML tags into react elements.

Installing React.js

Dev Ananth Arul — Fri, 05 Sep 2025 18:22:09 +0000

NPM
The name npm (Node Package Manager) stems from when npm first was created as a package manager for Node.js.

npm is the default package manager for Node.js, a JavaScript runtime environment.

All npm packages are defined in files called package.json.

The content of package.json must be written in JSON.

At least two fields must be present in the definition file: name and version.
{
"name" : "foo",
"version" : "1.2.3",
"description" : "A package for fooing things",
"main" : "foo.js",
"keywords" : ["foo", "fool", "foolish"],
"author" : "John Doe",
"licence" : "ISC"
}

NPX
The npx stands for Node Package Execute and it comes with the npm, when you installed npm above 5.2.0 version then automatically npx will be installed.

Npm is a tool that use to install packages.

Npx is a tool that use to execute packages.

CRA
Create React App aka CRA, is a javascript based command-line tool developed by Facebook and open source community to create a basic pre-configured starter boilerplate for a react application from where one can start development.

npx create-react-app my-app
cd my-app
npm start

Vite
Vite is a modern build tool designed for speed and efficiency, particularly when working with JavaScript frameworks like React. Developed by Evan You, the creator of Vue.js, Vite stands out due to its ability to deliver a fast and streamlined development experience.

Instant Server Start: The Vite development server skips bundling during development, resulting in near-instant startup.

Fast Hot Module Replacement (HMR): See real-time updates to your React components, speeding up iteration.

Optimized Production Builds: Vite uses Rollup to create efficient production bundles with features like code splitting.

Support for Modern Tools: Vite works seamlessly with TypeScript, JSX, and CSS preprocessors like Sass.

Closure, Fetch() and Axios in JavaScript

Dev Ananth Arul — Fri, 05 Sep 2025 17:58:05 +0000

Closure
The closure occurs when an inner function has access to variables in its outer function (outer scope), even when the outer function has finished executing.

function account (amount){
        let balance= amount;
        function withdraw(amt){
            balance= balance-amt;
            console.log(balance);

        }
           return withdraw;
       }
       const withdraw1=account(1000);
             withdraw1(100);
        const withdraw2=account(500);
            withdraw1(50);

Output
900
450

Fetch()
Fetch() returns a promise that resolves to a response object.
Url: The API endpoint from which data is fetched.
.response.json(): Parases the response as JSON.
.catch(error): Handles any errors that occur during the request.

 fetch("https://fakestoreapi.com/products")
      .then((res)=>{
       return res.json();
      })
      .then((json)=>{
        console.log(json);
      })
      .catch((err)=>{
        console.log(err);
      })

Axios
Axios is a open source javascript library use to make an HTTP request from web browsers. Automatically parses JSON(no need for response.json()).

 axios.get("https://fakestoreapi.com/products")
      .then((json)=>{
        console.log(json);
      })
      .catch((err)=>{
        console.log(err);
      })

Synchronization and Asynchronization in JavaScript

Dev Ananth Arul — Fri, 05 Sep 2025 17:35:11 +0000

Synchronization
Synchronization means tasks are executed one after another in sequence, where each task must finish before the next one starts.

Console.log("Task 1");
Console.log("Task 2");
Console.log("Task 3");

Output
Task 1
Task 2
Task 3

Asynchronization
Asynchronization do not wait for others to complete. some operations like timers, API calls,file reading run in the background and javascript moves on the next task. All functions are not asynchronization.

Console.log("Task 1");
SetTimeout(()=>{
Console.log("Task 2(after 2 seconds)");
},2000;
Console.log("Task 3");

Output
Task 1
Task 3
Task 2 (after 2 seconds)

Promise in JavaScript

Dev Ananth Arul — Tue, 02 Sep 2025 18:30:51 +0000

Promise:
A JavaScript Promise is an object representing the eventual completion (or failure) of an asynchronous operation and its resulting value. It allows for handling asynchronous tasks in a more structured and readable way compared to traditional callback-based approaches, especially when dealing with multiple sequential asynchronous operations (callback hell).

1. Promise creation

resolve() → tells that the task was successful.

reject() → tells that the task failed.

2. Promise consumption

.then() → runs when resolved (success).

.catch() → runs when rejected (error).

.finally() → always runs at the end (success or failure)

Example:

<script>

        function task(step, result) {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    console.log(step);
                    if (result) {
                        reject();
                    }
                    else {
                        resolve();
                    }
                }, 1000);
            })
        }
        task("Analysis")
            .then(() => task("plan"))
            .then(() => task("Design"))
            .then(() => task("Development"))
            .then(() => task("Testing", true))
            .then(() => task("Deployment"))
            .catch(() => console.log("Testing failed"))
            .finally(() => console.log("hello"))
    </script>