org.apache.http
Interfaces 
ConnectionReuseStrategy
HttpClientConnection
HttpConnection
HttpEntity
HttpEntityEnclosingRequest
HttpMessage
HttpProxyConnection
HttpRequest
HttpRequestFactory
HttpRequestInterceptor
HttpResponse
HttpResponseFactory
HttpResponseInterceptor
HttpServerConnection
Classes 
Header
HeaderElement
HttpHost
HttpStatus
HttpVersion
NameValuePair
ProxyHost
RequestLine
Scheme
StatusLine
Exceptions 
ConnectionClosedException
ConnectTimeoutException
HttpException
MethodNotSupportedException
NoHttpResponseException
ProtocolException
UnsupportedHttpVersionException