How I Built a Java App to Find Common Questions from PDFs (Perfect for Students!)

Kapil Bhabad — Fri, 25 Apr 2025 11:41:10 +0000

💡 The Problem
In diploma and degree courses (especially in India), students often collect notes from seniors, teachers, and online sources. These notes are usually in PDF format and filled with tons of questions.

But how do you:

Compare 5–6 different PDFs?

Find out which questions are repeating?

Save time while preparing for exams?

Simple answer: you build an app 😄

🛠️ The Tech Stack
I used Java as my main language because:

It has powerful libraries for working with files.

It’s cross-platform.

I wanted to improve my Java skills.

🔧 Libraries used:
PDFBox – to read and extract text from PDFs.

HashMap – to track frequency of questions.

Some basic file handling and string comparison.

👨‍💻 How the App Works
Input PDFs: The user selects multiple PDF files.

Extract Questions: The app reads each PDF and pulls out lines that look like questions (ending with ?).

Compare Questions: It uses a map to count how many times each question appears across all PDFs.

Output: A list of common questions, i.e., those that appeared more than once.

🧪 Sample Code Snippet
Here’s a simplified version of the question-detection logic:

java
Copy
Edit
if (line.trim().endsWith("?")) {
String question = line.trim();
questionMap.put(question, questionMap.getOrDefault(question, 0) + 1);
}
Pretty simple, right? The real challenge was text extraction and cleaning, especially because PDF formatting can be weird.

📦 Features I Plan to Add
GUI using JavaFX or Swing.

Export common questions to a new PDF.

Allow filtering by subject or keyword.

🚀 Why This Project Helped Me
I learned a lot about file parsing and text processing.

Solved a real-world problem for myself and my classmates.

Felt proud to build something helpful, even as a student.

🧠 Final Thoughts
You don’t need to build huge apps to make an impact. Even small tools that solve your personal problems can be super valuable.

If you’re a student who codes, look around — there’s probably something in your daily life you can automate or improve with programming.

💬 Let’s Connect!
If you're working on a similar project, or want help building your own student tools, I’d love to chat! Drop a comment or DM. 🚀

DEV Community: Kapil Bhabad

How I Built a Java App to Find Common Questions from PDFs (Perfect for Students!)