Daily Coding Challenges & Projects

Frontend Mini Project Challenge

CSS Animation Challenge

Challenge :

Create a “pulse” animation effect for a notification icon using only CSS.

Hint : Use arithmetic (modulus, division) to reverse the number.

Bonus : Add a hover scale-up transition.

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.icon {
  animation: pulse 2s infinite;
}

Try It Online :

CodePen

JSFiddle

Backend Challenge

Language Focus : Java & Kotlin

Java Task :

Build a RESTful API using Spring Boot that returns a list of employees in JSON.

Kotlin Task :

Create a Kotlin program that reads a JSON file and deserializes it into a list of objects using kotlinx.serialization.

Database Query Challenge

Problems on SQL - HR Database :

1. Find employees who report to no one (i.e., top-level managers).
2. Find the department(s) with the highest average salary.

Data Structures & Algorithms Challenge

• Easy:
• Problem :Reverse a string without using built-in reverse functions.
• Hint :Loop from the end of the string to the beginning.
• Medium:
• Problem : Find the longest common prefix in an array of strings.
• Hint :Start with the first string and compare character-by-character.
• Hard:
• Problem :Merge K sorted linked lists into one sorted list.
• Hint :Use a min-heap / priority queue.

Bug of the Day

Language : Java

Java Bug

Buggy Code:

public class Test {
    public static void main(String[] args) {
        Integer a = 128, b = 128;
        System.out.println(a == b); // true or false?
    }
}

Bug :Integer caching only works for values between -128 and 127.

Fix :Use .equals() for object value comparison.

📋 Daily Micro-Project

Backend :

Task :

Create a JWT-based login API in Java or Kotlin (Spring Boot / Ktor).

Bonus : Add token expiry and refresh logic.

Trivia: 5 Fun Facts

1. Java was initially named Oak.
2. Kotlin is developed by JetBrains.
3. The Spring framework was released in 2003.
4. JVM allows running code across platforms via bytecode.
5. Kotlin supports both OOP and functional programming styles.

Tool & Resource of the Day

Tool : ReqBin

A simple online REST API testing tool.

Resource Roundup :

• Baeldung – Deep dives into Java & Spring
• Kotlin Docs – Official language reference
• DevDocs – Fast documentation search

Interview Question of the Day

Daily Interview Questions

Frontend ( JS & CSS ) :
1. How can you animate elements using CSS only?
2. What is the z-index, and how does stacking context work?
3. Explain the CSS box model.
4. How do media queries work?

Backend ( Java, Kotlin ) :
1. What is the difference between == and .equals() in Java?
2. What is a data class in Kotlin?
3. How does garbage collection work in the JVM?
4. Difference between Mono and Flux in reactive programming?

Database :
1. What is a composite primary key?
2. What’s the difference between DELETE, TRUNCATE, and DROP?
3. Explain normalization in databases.

Others :
1. What is a JVM?
2. What is the difference between containerization and virtualization?

Daily Quiz Challenge

Frontend ( CSS & HTML ) :

1. What does position: sticky do?
2. Which property creates a stacking context?
3. What is the default value of z-index?

Backend ( Java & Kotlin ) :

1. What is the output of System.out.println(10 + 20 + "Hello")?
2. Which keyword is used for inheritance in Kotlin?
3. What is the default access modifier in Java?

Others :

• DB : What is the purpose of GROUP_CONCAT()?
• General : What does a container image contain?

Weekly Cross-Domain Activities ( July 18 to July 24, 2025 )

API of the Day:

JokeAPI : Build a random joke app with categories and flags (NSFW filter).

Linux/DevOps Tip :

Use htop, iotop, and iftop to monitor CPU, disk, and network usage on Linux servers.

Real-World Project of the Week ( July 18 to July 24, 2025 )

Project of the Week:

Build a Task Manager App

• Use React + Express + MongoDB
• Support CRUD: Tasks with due dates, priority, and status
• Implement filters (Today, Completed, Priority)

Collaborative Project:

Start a GitHub repo for this task manager and invite others to contribute (issues, PRs, README).

Case Study:

Analyze the GitHub UI/UX — Can you recreate the repository page using frontend tools?