org.springframework.integration.handler
Interfaces 
HandlerMethodResolver
MessageProcessor
Classes 
AbstractMessageHandler
AbstractMessageProcessor
AbstractReplyProducingMessageHandler
AbstractScriptExecutingMessageProcessor
BridgeHandler
DelayHandler
ExpressionEvaluatingMessageProcessor
LoggingHandler
MessageHandlerChain
MethodInvokingMessageHandler
MethodInvokingMessageProcessor
PayloadTypeMatchingHandlerMethodResolver
ServiceActivatingHandler
StaticHandlerMethodResolver