java.net
接口 
ContentHandlerFactory
CookiePolicy
CookieStore
DatagramSocketImplFactory
FileNameMap
SocketImplFactory
SocketOptions
URLStreamHandlerFactory
 
Authenticator
CacheRequest
CacheResponse
ContentHandler
CookieHandler
CookieManager
DatagramPacket
DatagramSocket
DatagramSocketImpl
HttpCookie
HttpURLConnection
IDN
Inet4Address
Inet6Address
InetAddress
InetSocketAddress
InterfaceAddress
JarURLConnection
MulticastSocket
NetPermission
NetworkInterface
PasswordAuthentication
Proxy
ProxySelector
ResponseCache
SecureCacheResponse
ServerSocket
Socket
SocketAddress
SocketImpl
SocketPermission
URI
URL
URLClassLoader
URLConnection
URLDecoder
URLEncoder
URLStreamHandler
枚举 
Authenticator.RequestorType
Proxy.Type
异常 
BindException
ConnectException
HttpRetryException
MalformedURLException
NoRouteToHostException
PortUnreachableException
ProtocolException
SocketException
SocketTimeoutException
UnknownHostException
UnknownServiceException
URISyntaxException