Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Theme : CSS Animation Effects

Challenge :

Create a bouncing ball animation using only CSS.

• The ball should move up and down smoothly.
• Bonus: Add a shadow that scales as the ball moves.

Try it online : CodePen / JSFiddle

Backend Challenge

Category : Java, Kotlin

Challenge :

Java : Write a program that implements a producer-consumer problem using threads and a shared queue.

Kotlin : Build a simple REST API using Ktor framework with one endpoint /hello that returns "Hello, World!".

Database Query Challenge

Problems on SQL - HR Database :

1. Write a query to find employees who earn the second highest salary in the company.
2. Write a query to list all employees along with their manager’s name (self-join on Employees table).

Data Structures & Algorithms Challenge

• Easy:
• Problem :Write a function to check if a string is a palindrome.
• Hint :Compare first and last characters moving inward.
• Medium:
• Problem : Implement a function to perform binary search on a sorted array.
• Hint :Use divide-and-conquer, compare middle element.
• Hard:
• Problem :Given an array of integers, find the maximum subarray sum using Kadane’s Algorithm.
• Hint :Keep track of current sum and max sum.

Bug of the Day

Language : Java, Kotlin

Buggy Code ( Java ):

public class Test {
    public static void main(String[] args) {
        int arr[] = new int[5];
        for(int i = 1; i <= 5; i++) {
            arr[i] = i * 2;
        }
        System.out.println("Done!");
    }
}

Challenge : Find and fix the issue. ( Hint : Think about array indexing in Java.)

📋 Daily Micro-Project

Type : Backend

Task :

Build a REST API in Java (Spring Boot) or Kotlin (Ktor) that has:

• GET /time → returns current server time.
• GET /greet?name=John → returns "Hello, John!".

Trivia: 5 Fun Facts

1. The Java mascot is called Duke.
2. Kotlin is the official language for Android development (announced by Google in 2017).
3. SQL was originally called SEQUEL (Structured English Query Language).
4. The first version of Java was released in 1995.
5. The term “bug” in software was popularized by Grace Hopper.

Tool & Resource of the Day

Tool : Postman

Use : Simplifies API testing and automation.

Resource Roundup :

• Postman Docs : API testing basics
• FreeCodeCamp Postman Crash Course
• REST API testing best practices (Postman Blog)

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What is the difference between relative, absolute, fixed, and sticky positioning in CSS?
2. How do CSS transitions differ from CSS animations?
3. Explain the concept of CSS specificity.
4. What are CSS pseudo-elements? Give examples.

Backend :
1. What are checked vs. unchecked exceptions in Java?
2. Explain the JVM, JRE, and JDK.
3. What is a coroutine in Kotlin?
4. How does dependency injection work in Spring Boot?

Database :
1. What is the difference between WHERE and HAVING in SQL?
2. Explain the concept of database normalization.
3. What is a composite primary key?

Others :
1. What is a deadlock in operating systems?
2. Explain CAP theorem in distributed systems.

Daily Quiz Challenge

Frontend ) :

1. Which CSS property controls the speed of an animation?
• animation-duration
• transition-timing
• speed
• delay
2. What is the output?

console.log("5" + 1);
console.log("5" - 1);

• 51 and 4
• 6 and 4
• 51 and NaN
• 6 and NaN
3. In CSS, which pseudo-class selects the first child element?
• :first-child
• :first-of-type
• :nth-child(0)
• :child-first

Backend :

1. In Java, which keyword is used to inherit a class?
• this
• extend
• extends
• inherit
2. Which of the following is true about Kotlin?
• It is fully interoperable with Java
• It cannot run on the JVM
• It is only used for Android
• It doesn’t support OOP
3. Which method is used to start a thread in Java?
• run()
• execute()
• start()
• begin()

Mixed :

1. Database : Which SQL keyword is used to remove duplicates from results?
• DISTINCT
• UNIQUE
• FILTER
• ONLY
2. Other : Who is known as the “father of the Java programming language”?
• James Gosling
• Bjarne Stroustrup
• Dennis Ritchie
• Guido van Rossum

Weekly Cross-Domain Activities ( August 15 to August 21, 2025 )

API of the Day:

Build a currency converter using the ExchangeRate API

Real-World Project of the Week ( August 15 to August 21, 2025 )

Project of the Week:

Idea : Build a personal expense tracker

• Frontend : React + Tailwind CSS
• Backend : Node.js + Express + MongoDB
• Features : Add, edit, delete expenses; filter by date and category; show monthly summaries.