java.net
Interfaces
| ContentHandlerFactory | This interface defines a factory for content handlers. | 
| 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 | A simple interface which provides a mechanism to map between a file name and a MIME type string. | 
| ProtocolFamily | Represents a family of communication protocols. | 
| SocketImplFactory | This interface defines a factory for socket implementations. | 
| SocketOption | A socket option associated with a socket. | 
| SocketOptions | Interface of methods to get/set socket options. | 
| URLStreamHandlerFactory | This interface defines a factory for  | 
Classes
| Authenticator | The class Authenticator represents an object that knows how to obtain authentication for a network connection. | 
| CacheRequest | Represents channels for storing resources in the ResponseCache. | 
| CacheResponse | Represent channels for retrieving resources from the ResponseCache. | 
| ContentHandler | The abstract class  | 
| 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  | 
| DatagramPacket | This class represents a datagram packet. | 
| DatagramSocket | This class represents a socket for sending and receiving datagram packets. | 
| DatagramSocketImpl | Abstract datagram and multicast socket implementation base class. | 
| HttpCookie | An HttpCookie object represents an HTTP cookie, which carries state information between server and user agent. | 
| HttpURLConnection | A URLConnection with support for HTTP-specific features. | 
| IDN | Provides methods to convert internationalized domain names (IDNs) between a normal Unicode representation and an ASCII Compatible Encoding (ACE) representation. | 
| Inet4Address | This class represents an Internet Protocol version 4 (IPv4) address. | 
| Inet6Address | This class represents an Internet Protocol version 6 (IPv6) address. | 
| InetAddress | This class represents an Internet Protocol (IP) address. | 
| InetSocketAddress | This class implements an IP Socket Address (IP address + port number) It can also be a pair (hostname + port number), in which case an attempt will be made to resolve the hostname. | 
| InterfaceAddress | This class represents a Network Interface address. | 
| JarURLConnection | A URL Connection to a Java ARchive (JAR) file or an entry in a JAR file. | 
| MulticastSocket | The multicast datagram socket class is useful for sending and receiving IP multicast packets. | 
| NetPermission | Legacy security code; do not use. | 
| NetworkInterface | This class represents a Network Interface made up of a name, and a list of IP addresses assigned to this interface. | 
| PasswordAuthentication | The class PasswordAuthentication is a data holder that is used by Authenticator. | 
| Proxy | This class represents a proxy setting, typically a type (http, socks) and a socket address. | 
| ProxySelector | Selects the proxy server to use, if any, when connecting to the network resource referenced by a URL. | 
| ResponseCache | Represents implementations of URLConnection caches. | 
| SecureCacheResponse | Represents a cache response originally retrieved through secure means, such as TLS. | 
| ServerSocket | This class implements server sockets. | 
| Socket | This class implements client sockets (also called just "sockets"). | 
| SocketAddress | This class represents a Socket Address with no protocol attachment. | 
| SocketImpl | The abstract class  | 
| SocketPermission | Legacy security code; do not use. | 
| StandardSocketOptions | Defines the standard socket options. | 
| URI | Represents a Uniform Resource Identifier (URI) reference. | 
| URL | Class  | 
| URLClassLoader | This class loader is used to load classes and resources from a search path of URLs referring to both JAR files and directories. | 
| URLConnection | The abstract class is the superclass of all classes that represent a communications link between the application and a URL. | 
| URLDecoder | Utility class for HTML form decoding. | 
| URLEncoder | Utility class for HTML form encoding. | 
| URLStreamHandler | The abstract class  | 
Exceptions
| 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. | 
Enums
| StandardProtocolFamily | Defines the standard families of communication protocols. | 
