By default, all beans are singletons, so whenever Application context gets created, they are all pre-loaded. If, specifically, any singleton bean has an attribute lazy-init="true" set, it will be lazy-loaded, i.e. it will be instantiated when the getBean method is called for the first time.

How are spring beans instantiated?

A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. Otherwise, a bean is simply one of many objects in your application. Beans, and the dependencies among them, are reflected in the configuration metadata used by a container.

When spring bean instances are created?

If a scope is set to singleton, the Spring IoC container creates exactly one instance of the object defined by that bean definition. This single instance is stored in a cache of such singleton beans, and all subsequent requests and references for that named bean return the cached object.