WebAppExample

A minimal Java web application intended for junior developers learning the basics of Java web apps, servlets, and JSPs. The app runs an embedded Tomcat server and serves static resources from src/main/webapp.

Prerequisites

• Java 25 (as configured in pom.xml)
• Maven 3.9+

Project Structure

• src/main/java — Java source code (including the embedded Tomcat bootstrap in uk.ac.ucl.main.Main)
• src/main/webapp — Static web resources and JSPs
• target — Build output (created by Maven)
• war-file — Packaged WAR output (created by Maven)

Compile

Build the project and produce a WAR file:

mvn clean package

This writes the WAR to war-file/.

Run (Embedded Tomcat)

First compile the project, then run the main class via Maven:

mvn clean compile exec:exec

By default the server starts on port 8080. Open:

http://localhost:8080

Configuration

You can configure the server using system properties or environment variables:

• SERVER_PORT — Port to bind (default: 8080)
• WEBAPP_DIR — Web resources directory (default: src/main/webapp/)
• CLASSES_DIR — Compiled classes directory (default: target/classes)

Example (using environment variables):

SERVER_PORT=9090 mvn clean compile exec:exec

Notes for Learners

• The entry point is uk.ac.ucl.main.Main in src/main/java/uk/ac/ucl/main/Main.java.
• Packaging as a WAR is useful if you want to deploy to an external Tomcat later.