Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Category : CSS Animation Effects

Challenge : Bouncing Ball Animation

Prompt :

Create a bouncing ball using only HTML and CSS (no JavaScript). The ball should bounce infinitely up and down.

Requirements :

• Use @keyframes
• Use transform: translateY() and animation-timing-function

Playground : https://codepen.io

Backend Challenge

Language Focus : Java, Kotlin

Java : REST API Endpoint

Prompt : Create a REST API in Java using Spring Boot that returns the current server time.

Hint : Use @RestController and @GetMapping.

Kotlin : File Line Counter

Prompt : Write a Kotlin program that takes a file path and returns the number of lines in that file.

Hint : Use File.readLines() and size.

Database Query Challenge

Problems on SQL - HR Database :

1. Highest Paid Employees per Department : Write a query to find the highest-paid employee in each department.
2. Department with No Hires This Year : List departments that haven't hired anyone in the current year.

Data Structures & Algorithms Challenge

• Easy:
• Problem :Check if a number is a palindrome
• Hint :Convert to string or reverse mathematically.
• Medium:
• Problem : Merge two sorted arrays without extra space
• Hint :Use two-pointer technique with in-place logic.
• Hard:
• Problem :Word Break Problem (DP)
• Hint :Use dynamic programming with a dictionary set.

Bug of the Day

Language Focus : Java

Java Bug

Buggy Code:

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

Challenge : What’s wrong and how to fix it?

📋 Daily Micro-Project

Type : Backend

Task :

Project : Build a Simple Authentication Middleware

• Description : Using Java (Spring Boot) or Kotlin (Ktor), create middleware that checks if a request has an "Authorization" header. If not, return 401.

Trivia: 5 Fun Facts

1. Who created the Linux kernel?
2. Which company developed Java?
3. Kotlin is officially supported by Google for Android development since?
4. SQL stands for?
5. What is the default port for HTTP?

Tool & Resource of the Day

Tool : Lottie by Airbnb

Use : Easily add animations to websites and apps using JSON

Link : https://lottiefiles.com/

Resource Roundup :

• Lottie + CSS Guide
• Animate.css Library
• W3Schools CSS Animation Docs

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are CSS transitions and how do they differ from animations?
2. What is specificity in CSS and how does it affect styling?
3. How do media queries work in responsive design?
4. What are pseudo-elements in CSS?

Backend :
1. Difference between JVM and JRE in Java?
2. What is Spring Boot and why is it useful?
3. How does Kotlin handle null safety?
4. What is the difference between checked and unchecked exceptions in Java?

Database :
1. What does the GROUP BY clause do in SQL?
2. What is a foreign key?
3. How is JOIN different from a subquery?

Others :
1. What is the difference between compiler and interpreter?
2. What are deadlocks in OS and how can they be avoided?

Daily Quiz Challenge

Frontend :

1. Which CSS property is used for animation duration?
• animation-speed
• transition-time
• animation-duration
• animate-duration
2. What is the default value of position in CSS?
• relative
• fixed
• static
• absolute
3. What does z-index do in CSS?
• Controls shadow
• Controls stacking order
• Controls background
• Controls transition speed

Backend :

1. Which HTTP method is used to update data?
• GET
• PUT
• POST
• PATCH
2. Which of the following is a thread-safe collection in Java?
• ArrayList
• LinkedList
• Vector
• HashMap
3. Kotlin keyword for a null-safe call is:
• :?
• ?.
• ifnull
• elvis

Others :

1. Which SQL clause groups data by columns?
• ORDER BY
• GROUP BY
• HAVING
• SELECT
2. Who is known as the father of computing?
• Dennis Ritchie
• Charles Babbage
• Alan Turing
• John McCarthy

Weekly Cross-Domain Activities ( July 25 to July 31, 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 ( July 25 to July 31, 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.