Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Category : CSS Animation Effects

Challenge :

Create a CSS-only bouncing ball animation that moves up and down infinitely.

Requirements :

• Use only HTML & CSS (no JavaScript)
• The ball should have a shadow effect when hitting the ground.

Example CSS Snippet :

.ball {
  width: 50px;
  height: 50px;
  background: red;
  border-radius: 50%;
  position: relative;
  animation: bounce 1s infinite ease-in-out;
}

@keyframes bounce {
  0%, 100% { top: 0; }
  50% { top: 100px; }
}

Backend Challenge

Category : Java, Kotlin

Problem :

Write a Java program that implements a multi-threaded file downloader.

Requirements :

• Accepts a URL and a file name as input.
• Downloads in multiple threads (splitting the file into chunks).
• Combines the chunks into a single file.

Database Query Challenge

Problems on SQL - HR Database :

1. Find employees earning more than the department average salary
2. List departments with no employees

Data Structures & Algorithms Challenge

• Easy:
• Problem :Reverse Implement a queue using two stacks.
• Hint :Use one stack for enqueue, another for dequeue.
• Medium:
• Problem : Implement merge sort for an array.
• Hint :Divide, sort recursively, merge.
• Hard:
• Problem :Find the longest common subsequence between two strings.
• Hint :Use dynamic programming table.

Bug of the Day

Language : Java

Java Bug

Buggy Code:

public class Main {
    public static void main(String[] args) {
        String s = null;
        if (s.equals("hello")) {
            System.out.println("Hello found!");
        }
    }
}

Challenge : Find and fix the bug so the code doesn’t throw an exception when s is null.

📋 Daily Micro-Project

Type : Backend

Task :

Create a Java REST API using Spring Boot that returns a JSON response of “Hello, World!” when accessed via /hello.

Trivia: 5 Fun Facts

1. Kotlin was officially supported for Android development by Google in 2017.
2. Java’s original name was Oak before being renamed.
3. SQL was originally called SEQUEL.
4. The first version of MySQL was released in 1995.
5. JVM allows Java to run on any OS with the same compiled bytecode.

Tool & Resource of the Day

Tool : Postman

Use : An API development and testing tool that makes sending requests and viewing responses easy.

Interview Question of the Day

Daily Interview Questions

Frontend :
1. How do CSS transitions differ from animations?
2. What is the difference between relative, absolute, and fixed positioning in CSS?
3. Explain the difference between inline, block, and inline-block elements.
4. What is the difference between CSS Grid and Flexbox?

Backend :
1. Explain the difference between method overloading and method overriding in Java.
2. How does garbage collection work in JVM?
3. What is the purpose of the volatile keyword in Java?
4. Difference between checked and unchecked exceptions in Java?

Database :
1. What is a foreign key in SQL?
2. Difference between clustered and non-clustered indexes?
3. What is the purpose of normalization?

Others :
1. What is multithreading, and why is it used?
2. Explain the concept of a virtual machine.

Daily Quiz Challenge

Frontend :

1. Which CSS property controls the speed of a transition?
• transition-speed
• transition-duration
• animation-speed
• transition-delay
2. What is the default position value in CSS?
• relative
• absolute
• static
• fixed
3. Which HTML element is used to define important text?
• <strong>
• <em>
• <b>
• <mark>

Backend :

1. Which Java keyword is used to inherit a class?
• this
• super
• extends
• implements
2. Which collection in Java does not allow duplicate elements?
• List
• Set
• Map
• ArrayList
3. Which method in Java starts a thread?
• execute()
• start()
• run()
• thread()

Mixed :

1. Database : Which SQL statement is used to extract data from a database?
2. Other : Which company created the Kotlin language?

Weekly Cross-Domain Activities ( August 01 to August 07, 2025 )

API of the Day:

Build a crypto tracker using the CoinGecko API.

Display current prices and 24h change of selected coins.

Linux/DevOps Tip :

Top 10 htop features for server monitoring (process tree, CPU graph, filter by user, etc.)

Real-World Project of the Week ( August 01 to August 07, 2025 )

Project of the Week:

Build a Task Manager App with React + Node.js + MongoDB (MERN Stack)

Collaborative Project:

Create an Open Source GitHub repo for “Interview Prep Hub” – collect user-submitted questions and answers.

Case Study:

Explore how Notion manages blocks and rich content – replicate a basic block-based note editor with contenteditable elements.