CachingMutablePicoContainer Wrapper around MutablePicoContainer which provides simple component caching. 
ComponentAccessor Provides static methods for accessing JIRA's managed components — that is, the components in the PicoContainer. 
ComponentAccessorWorker Worker class that insulates the API from the implementation dependencies in ManagerFactory etc. 
ComponentReference<T> Provides a way to obtain a dependency that cannot be injected due to a circular reference and without having to make numerous explicit calls to ComponentAccessor
OsgiComponentReference<T> Represents a reference like ComponentReference but for OSGi Components.