Calculate Area Circle Using Java Example

All programming language is designed to perform a mathematical operation. Java language is bundled with Math library for calculation in a simple and complex problem.

This tutorial will teach you on how your Java program Calculate the Area of a Circle based on user input value.

This tutorial will use a Scanner function and an Integer and Double data type for variables. Please follow all the steps to complete this tutorial.

Calculate the Area of a Circle in Java Steps

1. Create a new class and name it what you want.

2. Above your Main Class, Insert an import code to access the  Scanner library.

[java]import java.util.Scanner;[/java]

3. Declare a scanner and two variables inside your main method.

[java]Scanner input = new Scanner(System.in);
int radius;
double area;[/java]

4. After step 3, insert the code below for user input.

[java]System.out.print("Enter value of the circle radius: ");
radius = input.nextInt();[/java]

5. After step 4, insert the code below for the algorithm and output.

[java]area = Math.PI * radius * radius;
System.out.println("Area of a circle is: " + area);[/java]

6. Run your program and the output should look like the image below.

7. Complete Source Code.

[java]import java.util.Scanner;
public class CalculateCircleArea {
public static void main(String args[]){
Scanner input = new Scanner(System.in);
int radius;
double area;
System.out.print("Enter value of the circle radius: ");
radius = input.nextInt();
area = Math.PI * radius * radius;
System.out.println("Area of a circle is: " + area);
}
}[/java]

About The Calculate the Area of a Circle In Java

<figure class="wp-block-table is-style-stripes">
<table>
<tbody>
<tr>
<td><strong>Project Name:</strong></td>
<td>Calculate the Area of a Circle</td>
</tr>
<tr>
<td><strong>Language/s Used:</strong></td>
<td>JAVA</td>
</tr>
<tr>
<td><strong>Database:</strong></td>
<td>None</td>
</tr>
<tr>
<td><strong>Type:</strong></td>
<td>Desktop Application</td>
</tr>
<tr>
<td><strong>Developer:</strong></td>
<td>IT SOURCECODE</td>
</tr>
<tr>
<td><strong>Updates:</strong></td>
<td>0</td>
</tr>
</tbody>
</table><figcaption><em><strong>Calculate the Area of a Circle In Java</strong>- Project Information</em></figcaption></figure>

If you have any comment or suggestions about on How to Calculate the Area of a Circle in Java, feel free to leave your comment below, use the contact page of this website or use my contact information.

Email: [email protected]  |  Cell. No.: 09468362375

Technology stack and requirements

To run this Java project on your development machine, you need:

• Java Development Kit (JDK) 17 or higher. Download from adoptium.net (Eclipse Temurin) or oracle.com. JDK 21 LTS is recommended for new projects.
• Apache NetBeans or IntelliJ IDEA. Free IDEs with Java support, debugging, and GUI form designer.
• MySQL Server or MariaDB. Standalone install, or bundled with XAMPP for easier setup.
• MySQL Connector/J. JDBC driver JAR file included in the project’s lib folder or downloadable from dev.mysql.com.
• Git (optional). For version control if you want to extend the project.

Installing the source code

1. Extract the ZIP archive to a folder outside Program Files.
2. Open the project in NetBeans or IntelliJ. Choose File then Open Project and select the extracted folder.
3. Import the database. Open phpMyAdmin (with XAMPP) or MySQL Workbench, create a new database, and import the .sql file from the archive.
4. Update the JDBC connection string. Open the DatabaseConnection.java (or config file) and set your database host, name, user, and password.
5. Add the MySQL Connector JAR to the classpath. Right-click Libraries then Add JAR, select mysql-connector-java-x.x.x.jar.
6. Run the project. Press F6 (NetBeans) or Shift+F10 (IntelliJ) to run the main class.

Using this project for your BSIT capstone

• Chapter 1 (Introduction). Discuss the real-world problem this Java system solves. Cite Philippine business or academic use cases.
• Chapter 2 (RRL). Compare this project against 5-10 similar published works. Cite ACM, IEEE, or IJERT journal papers.
• Chapter 3 (Methodology). Include Use Case Diagram, DFD, ER Diagram, Class Diagram, and Sequence Diagram.
• Chapter 4 (Results). Screenshot each Swing form or JavaFX view with a caption explaining its role.
• Chapter 5 (Conclusion). Identify features for Version 2 (Spring Boot web version, REST API, mobile app).

Modules typical of Calculate the Area of a Circle

• Master data CRUD. JFrame + JTable for the primary entities the system manages.
• Transaction processing. Data entry forms with validation before saving.
• Reports. JasperReports or iText for formatted printable output.
• User management. Login with role-based permissions (Admin, Encoder, Viewer).
• Backup / restore. Export MySQL database to .sql file.

Common enhancements for capstone review

• Modernize UI. FlatLaf or Substance look-and-feel for modern appearance.
• Add REST API. Wrap business logic with Spring Boot for mobile or web front-ends.
• Docker container. Package with Dockerfile for portable deployment.
• Cloud deployment. Deploy to AWS Elastic Beanstalk or Azure App Service.

Project timeline for BSIT capstone

Typical BSIT teams complete a Java project of this scope in one full academic semester. Suggested timeline:

• Weeks 1-2. Requirements gathering, interview with target user, Chapter 1 documentation.
• Weeks 3-4. Design: use case, DFD, class diagram, ER diagram, mockup screens.
• Weeks 5-8. Core development: database in MySQL, main JFrames in NetBeans, CRUD operations.
• Weeks 9-11. Reports, printing, user roles. Test with sample data.
• Weeks 12-13. Documentation: Chapter 3-5 with screenshots.
• Week 14. Mock defense with adviser, corrections, final panel.

Panel questions this project typically gets

• Why did you choose Java over other languages? Prepare an answer about Java’s ecosystem (Swing/JavaFX for UI, JDBC for DB, Spring for modernization).
• How does the system handle concurrent access? Explain JDBC transactions, connection pooling, and locking.
• What is your backup and disaster recovery plan? Document backup script + demo restore.
• How would you deploy this in production? JAR bundling, Windows installer via Launch4j, or Spring Boot cloud deployment.

Deployment options after the defense

• Standalone JAR. Package with dependencies via Maven shade plugin, distribute as a single .jar file.
• Windows installer. Wrap the JAR with Launch4j + NSIS for a proper .exe installer.
• Spring Boot web rewrite. Migrate to Spring Boot + Thymeleaf for browser-based deployment.
• Docker container. Package with Dockerfile for portable deployment on any Docker-capable host.

Common defense pitfalls to avoid

• Empty database. Pre-populate 20-50 realistic records for meaningful demos.
• Missing error handling. Wrap SQL calls in try-catch with user-friendly messages.
• SQL injection vulnerability. Use PreparedStatement everywhere, never string-concatenate queries.
• No printable output. Add JasperReports for panel-expected printable reports.