org.apache.http.client
Interfaces 
AuthCache
AuthenticationHandler
AuthenticationStrategy
BackoffManager
ConnectionBackoffStrategy
CookieStore
CredentialsProvider
HttpClient
HttpRequestRetryHandler
RedirectHandler
RedirectStrategy
RequestDirector
ResponseHandler
ServiceUnavailableRetryStrategy
UserTokenHandler
Exceptions 
CircularRedirectException
ClientProtocolException
HttpResponseException
NonRepeatableRequestException
RedirectException