Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Theme : CSS Animation Effects

Challenge : Pulse Animation with CSS

Prompt :

Create a pulsing animation for a circle using only CSS. The circle should expand and fade out in a loop to simulate a heartbeat or radar pulse.

Requirements :

• Use @keyframes, transform, opacity, and animation-iteration-count: infinite;
• Create the circle using border-radius: 50%

Bonus : Accept a query param to filter by department.

Playground : Try it out on CodePen, JSFiddle, or CSSDeck

Backend Challenge

Language Focus : Java, Kotlin

Java : Create a Simple REST API

Task : Create a Spring Boot endpoint that returns a list of dummy employee data in JSON format.

Bonus : Use @RestController, @GetMapping, and Java collections.

Hint : Use @RestController, @GetMapping, and Java collections.

Kotlin : Sort Users by Join Date

Task : Write a Kotlin function that sorts a list of users by their joinDate in descending order.

Hint : Use Kotlin's sortedByDescending.

Database Query Challenge

Problems on SQL - HR Database :

1. Employees with No Manager : Find all employees who do not report to any manager.
2. Top 5 Departments with Highest Average Salary : List top 5 Departments with Highest Average Salary

Data Structures & Algorithms Challenge

• Easy:
• Problem :Find the Missing Number in a Sequence

Given an array of n-1 numbers from 1 to n, find the missing number.

• Hint :Use the sum formula: n(n+1)/2
• Medium:
• Problem : Implement a Stack using Two Queues
• Hint :Push normally, but for pop, dequeue all but last and re-enqueue.
• Hard:
• Problem :Trapping Rain Water

Given an array of heights, compute how much water it can trap.

• Hint :Use two-pointer or pre-computed left-max/right-max arrays

Bug of the Day

Language Focus : Java

Java Bug

Buggy Code:

public class Test {
    public static void main(String[] args) {
        int arr[] = new int[5];
        for(int i = 0; i <= arr.length; i++) {
            arr[i] = i * 2;
        }
        System.out.println("Done");
    }
}

Challenge : Find and fix the error.

📋 Daily Micro-Project

Type : Backend

Task :

Project : Create a Token Validator Middleware

• Description : In Java (Spring Boot) or Kotlin (Ktor), create a middleware that checks for an Authorization header and returns 401 if it's missing.

Bonus : Add dummy JWT structure validation.

Trivia: 5 Fun Facts

1. Kotlin was officially adopted by Google for Android in which year?
2. What does JVM stand for?
3. The Java language was initially named...?
4. Which company developed Kotlin?
5. Which keyword is used in Java to inherit a class?

Tool & Resource of the Day

Tool : Spring Initializr

Use : Quickly bootstrap Java Spring Boot projects

Link : https://start.spring.io/

Resource Roundup :

• Kotlin Docs
• Spring Boot Guide
• Java Cheat Sheet

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are media queries in CSS and how do they work?
2. What is the difference between em, rem, and px?
3. How do you create smooth transitions in CSS?
4. What is the purpose of z-index in CSS?

Backend :
1. What is a Java Bean in Spring?
2. How does exception handling work in Kotlin?
3. What is the difference between List and Set in Java?
4. Explain the use of @RequestMapping in Spring Boot.

Database :
1. What is normalization in databases?
2. Explain ACID properties.
3. Difference between VARCHAR and TEXT data types?

Others :
1. What is a virtual machine in computing?
2. What is garbage collection in Java?

Daily Quiz Challenge

Frontend :

1. Which CSS property controls animation speed?
• animation-duration
• animation-speed
• animation-timing
• duration-time
2. Which unit is relative to font-size of the element?
• em
• px
• %
• vh
3. What does transform: scale(1.5); do?
• Shrinks element
• Moves it
• Rotates it
• Enlarges it

Backend :

1. Which Java keyword is used to prevent inheritance?
• private
• static
• final
• protected
2. In Kotlin, which operator is used for null-safe calls?
• ??
• ?.
• :?
• !?
3. What is the default return type of Java's main() method?
• void
• int
• String
• boolean

Others :

1. Which SQL clause is used to rename a column in output?
• AS
• RENAME
• WITH
• NAME
2. Which company owns Java?
• Google
• Oracle
• IBM
• Microsoft

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.