Spring IOC Container | Beans, @Component, @Autowired & @Bean | Spring Boot Full Course #5

In this video, we will understand one of the most important concepts of the Spring Framework: the Spring IoC Container. Before Spring, we used to create and connect objects manually. But in a real application, object creation, dependency wiring, and lifecycle management become difficult to handle manually. This is where Spring comes in. In this lecture, we will understand how Spring creates objects, manages them as beans, injects dependencies, and gives us fully prepared objects from the container. Topics covered in this video: What is a Spring Bean? What is the Spring IoC Container? What is ApplicationContext? How AnnotationConfigApplicationContext works Why we use @Configuration How @ComponentScan finds classes How @Component creates beans What happens when we call getBean() Constructor Injection, Field Injection, and Setter Injection Why Constructor Injection is preferred How Spring resolves dependencies internally What happens when no matching bean exists What happens when multiple beans of the same type exist How @Primary works How @Qualifier works Custom bean names Difference between @Component and @Bean When to use @Bean This video is part of our Spring Framework and Spring Boot Full Course, where we are learning Spring from first principles with practical examples. By the end of this video, you will clearly understand how Spring manages objects internally and why IoC and Dependency Injection are the foundation of the Spring Framework. JAVA Beginner to Advance Series :    • Java Full Course 2026   Join System Design WhatsApp Group: https://www.whatsapp.com/channel/0029... Code and Notes: Github : https://github.com/adityatandon15/Spr... We have paid courses on DSA, Web Development , Blockchain, System Design & GenAI. Join Courses: https://strikes.in/ Coder Army Website: https://coderarmy.in/#home Coder Army App: https://play.google.com/store/apps/de... Connect with Aditya Tandon Instagram :   / adityatandon2   LinkedIn :   / adityatandon2   Twitter : https://x.com/adityatandon02 Timestamps: 00:00 Intro 01:15: Revisiting DI 05:30 IOC Container 06:58 Spring-context Dependency 10:58 Reflections in Java 15:22 Setting up with Spring IOC Container 28:53 Wiring Dependency using @Autowired 31:54 Types of DI 35:40 Why Constructor Injection is recommended 39:55 Internals of Spring managing beans 50:20 Adding Interfaces for Loose coupling 57:22 @Primary and @Qualifier Annotation 01:01:18 When @Component would fail 01:11:52 @Bean Annotation 01:20:12 DI in @Bean Configurations 01:29:01 @Primary & @Qualifier in @Bean 01:31:50 Why not add configurations in main 01:33:12 ApplicationContext vs BeanFactory