Daily Coding Challenges & Projects

Frontend Mini Project Challenge

CSS Animation Effects

Challenge :

Create a bouncing loader animation using only CSS.

Hint : Use @keyframes with transform: translateY() to simulate bouncing.

Try it Live : CodePen or JSFiddle

Backend Challenge

Java / Kotlin Focus

Problem : Java/Kotlin

Build a method that validates a password with the following rules:

• Minimum 8 characters
• At least one uppercase, one lowercase, one digit, one special character

Hint : Use regex or loop with ASCII checks.

Database Query Challenge

Problems on SQL - HR Database :

1. Find all employees who were hired on a Monday
2. List all employees and their department names, even if they are not assigned

Data Structures & Algorithms Challenge

• Easy:
• Problem :Given an array, return the second largest element.
• Hint :Use one pass or sort and pick second unique max.
• Medium:
• Problem :Detect a loop in a linked list.
• Hint : Floyd’s Tortoise and Hare algorithm.
• Hard:
• Problem :Given a list of intervals, merge all overlapping intervals.
• Hint :Sort intervals, then merge as you scan.

Bug of the Day

Language : Java

Java Bug

Buggy Code:

public class Buggy {
    public static void main(String[] args) {
        int x = 10;
        if (x = 5) {
            System.out.println("x is 5");
        }
    }
}

Find and fix the error :

Hint : Java doesn't allow assignment in condition like this!

📋 Daily Micro-Project

Backend Focus :

Task : Create a simple REST API in Kotlin using Ktor or Java with Spring Boot:

• GET /greet?name=John → returns { "message": "Hello, John!" }

Bonus : Add timestamp in response.

Trivia: 5 Fun Facts

1. The original Java compiler was written in C++.
2. Kotlin is officially supported for Android since 2017.
3. CSS animations can run on the GPU for smoother transitions.
4. The first SQL implementation was by IBM in the 1970s.
5. Unicode was developed to support global scripts and symbols.

Tool & Resource of the Day

Tool : Animista

Pre-built CSS animations you can copy and tweak.

Animista

Resource Roundup :

• Kotlin Docs – Official
• Java Regex Cheatsheet
• CSS Tricks: Animation Guide

Interview Question of the Day

Daily Interview Questions

Frontend ( CSS ) :
1. What is the difference between em, rem, and px?
2. How do transitions differ from animations in CSS?
3. How do media queries work in responsive design?
4. What is the difference between position: absolute and relative?

Backend ( Java/Kotlin ) :
1. What are the key differences between Java and Kotlin?
2. What is a lambda expression in Java?
3. How does JVM memory management work?
4. What is the difference between an interface and an abstract class?

Database ( SQL ) :
1. What does HAVING do in SQL?
2. Explain the ACID properties in databases.
3. How does a foreign key maintain referential integrity?

Others :
1. What is a daemon thread?
2. Explain garbage collection in JVM.

Daily Quiz Challenge

Frontend Quiz ( CSS ) :

1. Which CSS property controls the stacking order of elements?
2. What does transform: scale(1.5) do?
3. What’s the purpose of will-change in CSS?

Backend Quiz ( Java/Kotlin ) :

1. What is the output of System.out.println(10 + "20");?
2. In Kotlin, how do you define a nullable type?
3. Which keyword is used to inherit a class in Java?

Others :

• Databases :What’s the default order of ORDER BY if not specified?
• General :What does CI/CD stand for?

Mixed Quiz :

1. JavaScript + CSS : Can z-index affect inline elements?
2. SQL : What does COUNT(DISTINCT column) return?
3. Kotlin : What’s the difference between val and var?

Weekly Cross-Domain Activities ( July 11 to July 17, 2025 )

API of the Day:

Task : Build a stock price tracker using Twelve Data API.

https://twelvedata.com.

Linux/DevOps Tip :

Use htop instead of top for a better interactive process viewer.

Real-World Project of the Week ( July 11 to July 17, 2025 )

Project of the Week:

Build an Expense Tracker using React + Express + MongoDB.

Collaborative Project:

Join the GitHub project “open-budget-app” and contribute a budget visualization module

Case Study:

Analyze how GitHub Actions works and create a basic CI pipeline using YAML.