3.2.4. Managed Beans
Managed Beans are program components intended for implementation of the application’s business logic. "Managed" in this case means that the instance creation and dependency management is handled by the container, which is the main part of the Spring framework.
Managed Bean is a singleton by default, i.e., only one instance of such class exists in each application block. If a singleton bean contains mutable data in fields (in other words, has a state), it is necessary to synchronize access to such data.