# Java Version Upgrade Task

## Purpose

Upgrade an existing Java application from an older version to Java 21. Handles dependency updates, code modernization, testing validation, and deployment for Java version migrations.

## When to Use

- Upgrading from Java 8, 11, or 17 to Java 21
- Modernizing legacy Java applications
- Improving application performance and security
- Adopting new Java language features

## Input Requirements

- Current Java version and application details
- Target Java version (Java 21 recommended)
- Application dependencies and frameworks
- Current build system configuration
- Testing requirements
- Deployment environment details

## Process Steps

### 1. Current State Analysis

- Analyze current Java version and features used
- Identify deprecated APIs and patterns
- Assess code quality and technical debt
- Evaluate framework compatibility
- Review performance characteristics
- Document current configuration

### 2. Dependency Compatibility Check

- Check all dependencies for Java 21 compatibility
- Identify incompatible dependencies
- Research alternative libraries
- Plan dependency upgrade strategy
- Update Maven/Gradle dependencies
- Resolve dependency conflicts

### 3. Code Modernization

- Update code to use Java 21 features
- Replace deprecated APIs
- Implement modern Java patterns
- Optimize performance with new features
- Update exception handling
- Improve code quality

### 4. Build System Update

- Update Maven/Gradle configuration
- Update compiler plugin settings
- Update build profiles
- Update CI/CD pipeline configuration
- Test build process
- Validate build output

### 5. Testing and Validation

- Update test frameworks for Java 21
- Run comprehensive test suite
- Perform performance testing
- Conduct security testing
- Validate application functionality
- Test deployment process

### 6. Deployment Preparation

- Update deployment scripts
- Update container images
- Update AWS infrastructure
- Update monitoring configuration
- Prepare rollback procedures
- Plan deployment strategy

## Output Deliverables

- Java 21 compatible application
- Updated dependencies and build configuration
- Modernized code with Java 21 features
- Comprehensive test results
- Updated deployment configuration
- Migration documentation

## Success Criteria

- Application successfully upgraded to Java 21
- All dependencies updated and compatible
- Code modernized with Java 21 features
- All tests passing
- Performance maintained or improved
- Security vulnerabilities addressed
- Application deployed successfully

## Dependencies

- Java 21 JDK installed
- Updated build tools
- Compatible IDE
- Updated testing frameworks
- AWS infrastructure access

## Tools and Resources

- Java 21 JDK
- Maven/Gradle build tools
- IDE with Java 21 support
- Testing frameworks
- Performance testing tools
- Security scanning tools
- AWS CLI and tools