How does Spring Boot manage the order of bean initialization during application startup?

Spring Boot manages the order of bean initialization using the Spring IoC container (Inversion of Control). By default, Spring creates beans in the order of their dependencies: if bean A depends on bean B, then B is initialized before A.

To explicitly control the initialization order, you can use:

• @DependsOn — indicates that a bean should be initialized after the specified beans.
• @Order or the Ordered interface — define the order when initializing components, for example, when using collections of beans.
• Initialization through constructors and setters — dependencies are injected automatically, affecting the creation order.

Example with @DependsOn:

@Component
@DependsOn({"beanB"})
public class BeanA {
    // BeanA will be initialized after beanB
}

@Component
public class BeanB {
    // ...
}

Thus, Spring Boot guarantees the correct order of initialization based on dependencies between beans.