Learning Spring Boot from Zero to Cloud: Part 29 – @Configuration @Beans and RowMappers?

Welcome to another video in our Spring Boot Deep Dive series!
In this episode, we explore a powerful but often misunderstood part of the framework: @Bean methods inside @Configuration classes.

If you’ve ever wondered when to use @Bean instead of @Component, how Spring wires your dependencies behind the scenes, or how to avoid common pitfalls — this video is for you.

We’ll break down how Spring treats method calls inside @Configuration classes, and you’ll learn to use that behavior to wire beans like JdbcTemplate with custom RowMapper implementations.

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✅ What You’ll Learn

🎯 What’s really happening behind the scenes with @Bean
🔄 When to use @Bean instead of @Component
🧩 How Spring resolves dependencies between @Bean methods
🧠 The proxy magic and caching behavior inside @Configuration
🔧 Cleanly wiring beans together — like JdbcTemplate with a custom RowMapper
🚫 Common anti-patterns to avoid (yes, stop using new manually!)
🧪 How to override beans in your tests using @TestConfiguration

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⏱️ Timestamps

00:00 – Introduction
00:33 – What Is a @Bean and How Does It Work?
02:23 – @Bean vs @Component: Which One Should You Use?
05:25 – Manual Bean Wiring
08:48 – Inter-bean Method Calls and Caching
11:58 – Internals: How Spring Intercepts @Bean Method Calls
13:27 – When Should You Use @Bean?
14:44 – 3 Anti-Patterns: Using new , Logic-Heavy Config Classes, Mutable Singleton Beans
18:15 – Testing: Using @TestConfiguration to Override Beans
18:40 – Summary & Final Tips
21:13 – Code Session

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