org.apache.log4j.spi
Interfaces 
AppenderAttachable
Component
Configurator
Decoder
ErrorCode
ErrorHandler
HierarchyEventListener
LoggerEventListener
LoggerFactory
LoggerRepository
LoggerRepositoryEventListener
LoggerRepositoryEx
OptionHandler
RendererSupport
RepositorySelector
RepositorySelectorEx
Thresholdable
TriggeringEventEvaluator
Classes 
ComponentBase
DefaultRepositorySelector
ErrorItem
Filter
HierarchyEventListenerAdapter
LocationInfo
LoggingEvent
LoggingEventFieldResolver
NOPULogger
RootCategory
RootLogger
SimpleULogger
ThrowableInformation