📚 Main Topics

1. Dependency Injection in Spring Boot

   • Introduction to how Spring Boot facilitates dependency injection.
   • Importance of creating objects without using the new keyword.

2. Auto Wiring

   • Explanation of the concept of auto wiring in Spring Boot.
   • How to use the @Autowired annotation to automatically connect dependencies.

3. Types of Dependency Injection

   • Field InjectionUsing @Autowired directly on fields.
   • Constructor InjectionPassing dependencies through the constructor.
   • Setter InjectionUsing setter methods to inject dependencies.

4. Loose Coupling with Interfaces

   • Creating an interface (e.g., Computer) to allow for flexible dependency management.
   • Implementing the interface in different classes (e.g., Laptop and Desktop).

5. Handling Multiple Implementations

   • Issues that arise when multiple beans of the same type exist.
   • Solutions using @Primary and @Qualifier annotations to resolve ambiguity.

✨ Key Takeaways

• Auto WiringSimplifies the process of connecting dependencies in Spring Boot applications.
• Field vs. Constructor vs. Setter InjectionEach method has its use cases, with constructor injection generally being preferred for immutability and clarity.
• Loose CouplingUsing interfaces allows for more flexible and maintainable code, enabling easier changes in implementations.
• Resolving AmbiguityWhen multiple beans are present, use @Primary to indicate a preferred bean or @Qualifier to specify which bean to use.

🧠 Lessons Learned

• Best PracticesAlways aim for loose coupling in your code to enhance maintainability and flexibility.
• Understanding AnnotationsFamiliarize yourself with Spring annotations like @Autowired, @Primary, and @Qualifier to effectively manage dependencies.
• DebuggingBe prepared to handle common errors related to bean creation and dependency resolution in Spring applications.