Course Overview
Transform your Java development skills with this comprehensive course on generics - one of Java's most powerful yet misunderstood features. This course takes you from basic type safety concepts to advanced patterns used in production systems and pairs the lessons with the 128-java-generics Agent Skill for guided code reviews and refactoring.
🎯 Learning Objectives
By the end of this course, you will be able to:
- Eliminate ClassCastException through proper generic type usage
- Design flexible APIs using PECS (Producer Extends Consumer Super) principle
- Implement type-safe collections without raw types or unsafe casts
- Handle complex inheritance scenarios with bounded type parameters
- Integrate generics with modern Java features like Records and sealed types
- Apply advanced patterns like type tokens and heterogeneous containers
- Optimize performance through proper generic design choices
- Use the Java Generics Agent Skill to review and improve generics in real projects
📋 Prerequisites
- Java Fundamentals: Classes, interfaces, inheritance, and collections
- Object-Oriented Programming: Understanding of polymorphism and encapsulation
- Basic Maven/Gradle: Ability to compile and run Java projects
- Development Environment: Java 17+ with IDE support
🧩 Companion Agent Skill
Use the 128-java-generics skill while working through the exercises. It provides a portable Agent Skill workflow across supported coding agents.
- Skill registry:
128-java-genericson Skills.sh - Skill source:
skills/128-java-generics - Install:
npx skills add https://github.com/jabrena/plinth --skill 128-java-generics - Example request:
Review the Java classes in the current context and improve their generics usage with the 128-java-generics skill.
⏱️ Course Duration & Difficulty
- Total Time: 12-15 hours
- Difficulty: Intermediate to Advanced
- Format: Self-paced with hands-on exercises
- Certification: Available upon completion
📚 Course Structure
🏗️ Module 1: Foundations (2-3 hours)
Core Concepts and Type Safety
- Understanding the problem generics solve
- Raw types vs parameterized types
- Diamond operator and type inference
- Basic generic syntax and conventions
🎯 Learning Goals: Eliminate raw types and understand basic generic syntax
📝 Assessment: Convert legacy code to use proper generics
🔄 Module 2: Wildcards & PECS (3-4 hours)
Variance and Flexible APIs
- Understanding covariance and contravariance
- Producer Extends Consumer Super principle
- Bounded wildcards in practice
- Wildcard capture and helper methods
🎯 Learning Goals: Design flexible APIs that accept multiple related types
📝 Assessment: Implement utility methods with proper wildcards
🚀 Module 3: Advanced Patterns (4-5 hours)
Complex Generics and Edge Cases
- Type erasure and runtime implications
- Generic inheritance and self-bounded types (CRTP)
- Safe varargs and heap pollution prevention
- Type tokens for runtime type information
🎯 Learning Goals: Handle complex scenarios and avoid common pitfalls
📝 Assessment: Build type-safe heterogeneous container
🌍 Module 4: Real-World Applications (3-4 hours)
Production Patterns and Integration
- Serialization with generic types
- Integration with modern Java features (Records, sealed types)
- Performance considerations and optimizations
- Migration strategies for legacy codebases
🎯 Learning Goals: Apply generics in real-world scenarios
📝 Assessment: Refactor existing project with comprehensive generics
✅ Module 5: Assessment (1-2 hours)
Knowledge Validation and Next Steps
- Comprehensive coding challenges
- Code review exercises
- Best practices checklist
🎯 Learning Goals: Validate mastery
📝 Assessment: Complete the capstone project, then use the 128-java-generics skill for a final review
Ready to master Java Generics? Start with Module 1: Foundations or choose your preferred learning path above.