Spring beans are the fundamental building blocks of the Spring Framework; they are objects that are instantiated, assembled, and managed by the Spring Inversion of Control (IoC) container. The term "bean" in the context of Spring is used to describe a managed object, not a specific type or class of object. Any object that is controlled by the Spring container can be referred to as a Spring bean.
The Spring IoC container is responsible for creating beans according to the configuration metadata provided by the developer. This metadata can be supplied in various forms, such as XML configuration files, annotations in the code, or Java-based configuration. The container handles the lifecycle of these beans, including their creation, initialization, wiring with other beans, and destruction when no longer needed.
Beans are defined with specific metadata that tells the container how to create and manage them. This metadata includes information such as the class of the object, its scope (e.g., singleton or prototype), and dependencies on other beans, which are injected into the bean typically via setter methods or constructors. This process of dependency injection is a core feature of the Spring Framework, allowing for loose coupling between components and easier testability.
