…e-readme

Add Java 21 examples

Changes made:
- English.java: Updated comments to reflect Java 21 and better document features
- Letters.java: Replaced instanceof if statement with switch pattern matching, added multiple type cases and null handling
- Main.java: Enhanced with Java 21 pattern matching switch, null handling, and guarded patterns with 'when' clause

All files now fully leverage Java 21 features including:
- Pattern matching in switch expressions
- Null case handling in switch
- Guarded patterns with when clauses
- Enhanced type pattern matching

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

- Changed title to indicate Java 10-21 feature demonstrations
- Added repository structure section mapping files to features
- Enhanced feature descriptions with explanations
- Added compilation requirements specifying Java 21 needed
- Improved formatting and organization for better clarity

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

…FWnhi4nETjUg6zX

Upgrade trail src code to Java 21

…RhmQ

Update README to accurately reflect Java 21 repository content

Added two new files showcasing Java 25 features:
- Main25.java: Demonstrates flexible constructor bodies (JEP 482) and primitive type patterns (JEP 455)
- StreamGatherers25.java: Demonstrates the Stream Gatherers API with examples of windowFixed, windowSliding, fold, and mapConcurrent

Updated README.md to include:
- Java 25 section in features listing
- New files in repository structure
- Updated title and compilation requirements

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

…3fM7

Add Java 25 features demonstration

Remove outdated entries (BlueJ, J2ME) and add comprehensive coverage for:
- Modern IDEs (IntelliJ IDEA, VS Code, Eclipse, NetBeans)
- Build directories (out/, target/, build/, bin/, dist/)
- OS-specific files (macOS, Windows, Linux)
- Maven and Gradle build artifacts
- Temporary and backup files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

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Update .gitignore with modern Java project patterns