ContentHandlerFactory Defines a factory which is responsible for creating a ContentHandler
CookiePolicy CookiePolicy implementations decide which cookies should be accepted and which should be rejected. 
CookieStore A CookieStore object represents a storage for cookie. 
DatagramSocketImplFactory This interface defines a factory for datagram socket implementations. 
FileNameMap Defines a scheme for mapping a filename type to a MIME content type. 
ProtocolFamily Represents a family of communication protocols. 
SocketImplFactory This interface defines a factory for socket implementations. 
SocketOptions Defines an interface for socket implementations to get and set socket options. 
URLStreamHandlerFactory Defines a factory which creates an URLStreamHandler for a specified protocol. 


Authenticator An implementation of this class is able to obtain authentication information for a connection in several ways. 
CacheRequest CacheRequest is a kind of channel for storing resource data in the ResponseCache
CacheResponse A response cache entry. 
ContentHandler This class converts the content of a certain format (i.e. 
CookieHandler A CookieHandler object provides a callback mechanism to hook up a HTTP state management policy implementation into the HTTP protocol handler. 
CookieManager CookieManager provides a concrete implementation of CookieHandler, which separates the storage of cookies from the policy surrounding accepting and rejecting cookies. 
DatagramPacket This class represents a datagram packet which contains data either to be sent or received through a DatagramSocket
DatagramSocket This class implements a UDP socket for sending and receiving DatagramPacket
DatagramSocketImpl The abstract superclass for datagram and multicast socket implementations. 
HttpCookie An HttpCookie object represents an http cookie, which carries state information between server and user agent. 
HttpURLConnection An URLConnection for HTTP (RFC 2616) used to send and receive data over the web. 
IDN Converts internationalized domain names between Unicode and the ASCII Compatible Encoding (ACE) representation. 
Inet4Address An IPv4 address. 
Inet6Address An IPv6 address. 
InetAddress An Internet Protocol (IP) address. 
InetSocketAddress This class represents a socket endpoint described by a IP address and a port number. 
InterfaceAddress Identifies one of a network interface's addresses. 
JarURLConnection This class establishes a connection to a jar: URL using the JAR protocol. 
MulticastSocket This class implements a multicast socket for sending and receiving IP multicast datagram packets. 
NetPermission Legacy security code; do not use. 
NetworkInterface This class is used to represent a network interface of the local device. 
PasswordAuthentication This immutable class is a data structure that encapsulates username and password which is used by the Authenticator class. 
Proxy This class represents proxy server settings. 
ProxySelector Selects the proxy server to use, if any, when connecting to a given URL. 
ResponseCache Caches URLConnection responses. 
SecureCacheResponse A secure cache response represents data which is originally retrieved over a secure connection. 
ServerSocket This class represents a server-side socket that waits for incoming client connections. 
Socket Provides a client-side TCP socket. 
SocketAddress This abstract class represents a protocol-independent base for socket-endpoint representing classes. 
SocketImpl This class is the base of all streaming socket implementation classes. 
SocketPermission Legacy security code; do not use. 
URI A Uniform Resource Identifier that identifies an abstract or physical resource, as specified by RFC 2396
URL A Uniform Resource Locator that identifies the location of an Internet resource as specified by RFC 1738
URLClassLoader This class loader is responsible for loading classes and resources from a list of URLs which can refer to either directories or JAR files. 
URLConnection A connection to a URL for reading or writing. 
URLDecoder This class is used to decode a string which is encoded in the application/x-www-form-urlencoded MIME content type. 
URLEncoder This class is used to encode a string using the format required by application/x-www-form-urlencoded MIME content type. 
URLStreamHandler The abstract class URLStreamHandler is the base for all classes which can handle the communication with a URL object over a particular protocol type. 


Authenticator.RequestorType Enumeration class for the origin of the authentication request. 
Proxy.Type Enum class for the proxy type. 


BindException Signals that an error occurred while attempting to bind a socket to a local address and port. 
ConnectException Signals that an error occurred while attempting to connect a socket to a remote address and port. 
HttpRetryException Thrown to indicate that a HTTP request needs to be retried but cannot be retried automatically, due to streaming mode being enabled. 
MalformedURLException Thrown to indicate that a malformed URL has occurred. 
NoRouteToHostException Signals that an error occurred while attempting to connect a socket to a remote address and port. 
PortUnreachableException Signals that an ICMP Port Unreachable message has been received on a connected datagram. 
ProtocolException Thrown to indicate that there is an error in the underlying protocol, such as a TCP error. 
SocketException Thrown to indicate that there is an error creating or accessing a Socket. 
SocketTimeoutException Signals that a timeout has occurred on a socket read or accept. 
UnknownHostException Thrown to indicate that the IP address of a host could not be determined. 
UnknownServiceException Thrown to indicate that an unknown service exception has occurred. 
URISyntaxException Checked exception thrown to indicate that a string could not be parsed as a URI reference.