| Login | Provides simplified handling of login properties when creating a
  ServiceFactory. | 
| OmeroContext | Provides static access for the creation of singleton and non-singleton
 application contexts. | 
| OmeroContext.Locator | provides access to the protected methods of
 ContextSingletonBeanFactoryLocatorwhich cannot be used externally. | 
| Preference | Definition of a server configuration variable ("preference") along with its
 mutability, visibility, aliases and other important information. | 
| PreferenceContext | Central configuration for OMERO properties from (in order):
 
 Any injected Propertiesinstances
 JavaSystem.getProperties()Any configured property files
 
 
 As of OMERO 4.2, server configurations are not stored in Java's
 Preferences API but in an IceGrid xml file under etc/grid of the server
 installation. | 
| Principal | implementation of Principal. | 
| Roles | encapsulates the naming scheme for critical system groups and accounts. | 
| Server | Provides simplified handling of server properties when creating a
  ServiceFactory. | 
| ServiceFactory | Entry point for all client calls. | 
| SessionInitializer | Manages the creation of a single  Session created via the injected
  ISession service. | 
| SimpleEventContext |  | 
| UpgradeCheck | Contacts a given URL which should be an OME server which will return either
 an empty String or a URL which points to a needed upgrade. |