Memory Leak Test Application

A Spring Boot application that demonstrates controlled memory leaks for educational and testing purposes.

� Quick Start

Prerequisites

• Java 8+ and Maven 3.6+
• 4GB+ RAM recommended

1. Build & Run

# Build the application
mvn clean package

# Start the application (default port: 8080)
java -Xms256m -Xmx512m -XX:+UseG1GC -XX:+PrintGC -jar target/memory-leak-app-1.0.0.jar

# OR run on custom port (e.g., 9090)
java -Xms256m -Xmx512m -XX:+UseG1GC -XX:+PrintGC -Dserver.port=9090 -jar target/memory-leak-app-1.0.0.jar

2. Test the Memory Leak

# Check application health
curl http://localhost:8080/api/health

# Trigger memory growth (run multiple times)
curl -X POST http://localhost:8080/api/process

# View memory statistics
curl http://localhost:8080/api/stats

# Clear caches (for testing)
curl -X POST http://localhost:8080/api/clear

3. Automated Testing

# Make script executable
chmod +x memory-loop.sh

# Simple continuous testing (1 second intervals)
./memory-loop.sh simple

# Long-term gradual testing (30 second intervals)
./memory-loop.sh slow

# Auto-restart mode (handles crashes automatically)
./memory-loop.sh auto-restart

# View all options
./memory-loop.sh help

📊 API Endpoints

Method	Endpoint	Description
POST	/api/process	Create memory leak objects (~5-15KB)
GET	/api/stats	View detailed memory statistics
POST	/api/clear	Clear all caches
GET	/api/health	Health check with memory usage

🎯 Expected Behavior

• Memory Growth: Gradual increase over 3-4 hours
• GC Activity: Increasing frequency as memory fills up
• Eventual Crash: OutOfMemoryError after sustained load

⚠️ Important Notes

• Educational Purpose: Designed for memory leak demonstration only
• Monitor Resources: Watch system memory during testing
• Clean Shutdown: Use /api/clear before stopping the application

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Quick Demo:

mvn clean package && java -Xms256m -Xmx512m -XX:+UseG1GC -jar target/memory-leak-app-1.0.0.jar &
sleep 10 && ./memory-loop.sh slow

# Navigate to your workspace
cd /your/workspace/directory

# If you already have the project, navigate to it
cd memory_overloader

# Verify project structure
ls -la
# Should show: pom.xml, src/, README.md, test-scenarios.sh

Project Structure

memory_overloader/
├── pom.xml                          # Maven build configuration
├── README.md                        # This file
├── test-scenarios.sh               # Automated test scripts
├── src/
│   └── main/
│       ├── java/
│       │   └── com/test/memoryleak/
│       │       ├── MemoryLeakApplication.java      # Main application
│       │       ├── controller/
│       │       │   └── MemoryLeakController.java   # REST endpoints
│       │       ├── service/
│       │       │   ├── MemoryLeakService.java      # Core leak logic
│       │       │   └── CircularReferenceManager.java # Reference management
│       │       └── model/
│       │           └── HeavyObject.java            # Memory-heavy object
│       └── resources/
│           └── application.properties              # App configuration
└── target/                          # Build output (created after build)

🔧 Build Instructions

1. Clean Build

# Navigate to project root
cd /path/to/memory_overloader

# Clean any previous builds and compile
mvn clean compile

# Full build with tests
mvn clean package

2. Verify Build Success

# Check if JAR was created
ls -la target/memory-leak-app-1.0.0.jar

3. Build Troubleshooting

Common Issues:

Java Version Mismatch:

# If you get Java version errors
export JAVA_HOME=/path/to/java8
mvn clean package -Djava.version=1.8

Maven Dependencies:

# Force dependency refresh
mvn clean package -U

# Clear local repository cache
rm -rf ~/.m2/repository/com/test/memory-leak-app
mvn clean package

Compilation Errors:

# Verbose build for debugging
mvn clean package -X -e

This application effectively demonstrates how memory leaks occur, persist, and impact application performance in a controlled environment.