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☕ Java + Spring Boot Interview Preparation Guide

Topics: Java Core • Spring Boot • JPA/Hibernate • Security & JWT • REST API • System Design

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📋 Table of Contents

1. ☕ Java Core — Q1–Q8
2. 🌱 Spring Boot — Q9–Q14

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What is BIOS and How Does it Work?

BIOS, short for Basic Input/Output System, is like the heart of a computer's hardware. It's a firmware program stored on a chip on the computer's motherboard.

Here's a breakdown of how a BIOS works:

1. Initialization ⚙️

When you power on your computer, the CPU (Central Processing Unit) starts executing code from a predefined memory location, which is the BIOS ROM (Read-Only Memory). This code initializes critical hardware components like the CPU, RAM, storage devices, and input/output devices.

2. POST (Power-On Self-Test) 🔬

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Web Servers: Powering the Internet

Web servers are the unsung heroes of the internet, quietly processing billions of requests each day to deliver web pages and content to users worldwide. In this article, we'll explore what web servers are, how they work, their key components, types, functions, and the critical role they play in ensuring the functionality and security of websites and web applications.

1. What are Web Servers?

At its core, a web server is specialized software or hardware that stores, processes, and serves web pages and other web-related content to users over the internet. It acts as the intermediary between a user's web browser and the web applications or websites they wish to access. Without web servers, the internet as we know it today would not exist.

2. How They Work

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Cookies 🍪 in a Nutshell

What is a Cookie?

A cookie is a small piece of data that websites store on a user's device, often in their web browser, when the user interacts with the site.

Types of Cookies

• Session Cookies: Temporary, for the duration of a user's session, used for maintaining login status, expires when the browser closes.
• Persistent Cookies: Have an expiration date set by the website, can remain after the browser closes, used for preferences, language settings, etc.

Usage

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HTTP in a Nutshell

HTTP (Hypertext Transfer Protocol) is the foundation of data communication on the internet. It's a protocol that allows clients (usually web browsers) to request resources (like web pages) from servers.

HTTP Request

HTTP Methods

• GET: Retrieve data.
• POST: Send data.

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Client-Server Architecture in a Nutshell

Client-server architecture is a network model in which computing tasks are divided between clients (users' devices) and servers (centralized computers). Clients request services or resources from servers over a network.

Client

A client is a device or application that initiates requests for services or data from a server. Common client devices include computers, smartphones, and tablets.

Server

A server is a powerful computer or software application responsible for providing services or data to clients. Servers are usually located in data centers and are optimized for high performance and reliability.

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#create a new repository on the command line

echo "# Anchor-test" >> README.md
git init
git add README.md
git commit -m "first commit"
git branch -M main
git remote add origin https://github.com/user-name/repository.git
git push -u origin main

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Insert an Image

![](path of the Image)

if image file name contains any spaces you can %20 for that spaces.

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Github also support HTML img tag

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{
    "$schema": "https://aka.ms/terminal-profiles-schema",
    "copyOnSelect": false,
    "defaultProfile": "{574e775e-4f2a-5b96-ac1e-a2962a402336}",
    // Add custom keybindings to this array.
    // To unbind a key combination from your defaults.json, set the command to "unbound".
    // To learn more about keybindings, visit https://aka.ms/terminal-keybindings
    "keybindings": 
    [
        // Copy and paste are bound to Ctrl+Shift+C and Ctrl+Shift+V in your defaults.json.