public class

InetAddress

extends Object
implements Serializable
java.lang.Object
   ↳ java.net.InetAddress
Known Direct Subclasses

Class Overview

The Internet Protocol (IP) address representation class. This class encapsulates an IP address and provides name and reverse name resolution functions. The address is stored in network order, but as a signed (rather than unsigned) integer.

Summary

Public Methods
boolean equals(Object obj)
Compares this InetAddress instance against the specified address in obj.
byte[] getAddress()
Returns the IP address represented by this InetAddress instance as a byte array.
static InetAddress[] getAllByName(String host)
Gets all IP addresses associated with the given host identified by name or IP address in dot-notation.
static InetAddress getByAddress(String hostName, byte[] ipAddress)
Returns the InetAddress corresponding to the array of bytes, and the given hostname.
static InetAddress getByAddress(byte[] ipAddress)
Returns the InetAddress corresponding to the array of bytes.
static InetAddress getByName(String host)
Returns the address of a host according to the given host string name host.
String getCanonicalHostName()
Gets the fully qualified domain name for the host associated with this IP address.
String getHostAddress()
Gets the textual representation of this IP address.
String getHostName()
Gets the host name of this IP address.
static InetAddress getLocalHost()
Gets the local host address if the security policy allows this.
int hashCode()
Gets the hashcode of the represented IP address.
boolean isAnyLocalAddress()
Returns whether this is a wildcard address or not.
boolean isLinkLocalAddress()
Returns whether this address is a link-local address or not.
boolean isLoopbackAddress()
Returns whether this address is a loopback address or not.
boolean isMCGlobal()
Returns whether this address is a global multicast address or not.
boolean isMCLinkLocal()
Returns whether this address is a link-local multicast address or not.
boolean isMCNodeLocal()
Returns whether this address is a node-local multicast address or not.
boolean isMCOrgLocal()
Returns whether this address is a organization-local multicast address or not.
boolean isMCSiteLocal()
Returns whether this address is a site-local multicast address or not.
boolean isMulticastAddress()
Returns whether this address is an IP multicast address or not.
boolean isReachable(int timeout)
Tries to reach this InetAddress.
boolean isReachable(NetworkInterface netif, int ttl, int timeout)
Tries to reach this InetAddress.
boolean isSiteLocalAddress()
Returns whether this address is a site-local address or not.
String toString()
Returns a string containing a concise, human-readable description of this IP address.
[Expand]
Inherited Methods
From class java.lang.Object

Public Methods

public boolean equals (Object obj)

Compares this InetAddress instance against the specified address in obj. Two addresses are equal if their address byte arrays have the same length and if the bytes in the arrays are equal.

Parameters
obj the object to be tested for equality.
Returns
  • true if both objects are equal, false otherwise.

public byte[] getAddress ()

Returns the IP address represented by this InetAddress instance as a byte array. The elements are in network order (the highest order address byte is in the zeroth element).

Returns
  • the address in form of a byte array.

public static InetAddress[] getAllByName (String host)

Gets all IP addresses associated with the given host identified by name or IP address in dot-notation. The IP address is resolved by the configured name service. If the host name is empty or null an UnknownHostException is thrown. If the host name is a dotted IP address string an array with the corresponding single InetAddress is returned.

Parameters
host the host's name or IP to be resolved to an address.
Returns
  • the array of addresses associated with the specified host.
Throws
UnknownHostException if the address lookup fails.

public static InetAddress getByAddress (String hostName, byte[] ipAddress)

Returns the InetAddress corresponding to the array of bytes, and the given hostname. In the case of an IPv4 address there must be exactly 4 bytes and for IPv6 exactly 16 bytes. If not, an UnknownHostException will be thrown.

The host name and IP address are not validated.

The hostname either be a machine alias or a valid IPv6 or IPv4 address format.

The high order byte is ipAddress[0].

Parameters
hostName the string representation of hostname or IP address.
ipAddress either a 4 (IPv4) or 16 (IPv6) byte long array.
Returns
  • an InetAddress instance representing the given IP address and hostname.
Throws
UnknownHostException if the given byte array has no valid length.

public static InetAddress getByAddress (byte[] ipAddress)

Returns the InetAddress corresponding to the array of bytes. In the case of an IPv4 address there must be exactly 4 bytes and for IPv6 exactly 16 bytes. If not, an UnknownHostException is thrown.

The IP address is not validated by a name service.

The high order byte is ipAddress[0].

Parameters
ipAddress is either a 4 (IPv4) or 16 (IPv6) byte long array.
Returns
  • an InetAddress instance representing the given IP address ipAddress.
Throws
UnknownHostException if the given byte array has no valid length.

public static InetAddress getByName (String host)

Returns the address of a host according to the given host string name host. The host string may be either a machine name or a dotted string IP address. If the latter, the hostName field is determined upon demand. host can be null which means that an address of the loopback interface is returned.

Parameters
host the hostName to be resolved to an address or null.
Returns
  • the InetAddress instance representing the host.
Throws
UnknownHostException if the address lookup fails.

public String getCanonicalHostName ()

Gets the fully qualified domain name for the host associated with this IP address. If a security manager is set, it is checked if the method caller is allowed to get the hostname. Otherwise, the textual representation in a dotted-quad-notation is returned.

Returns
  • the fully qualified domain name of this IP address.

public String getHostAddress ()

Gets the textual representation of this IP address.

Returns
  • the textual representation of this host address in form of a dotted string.

public String getHostName ()

Gets the host name of this IP address. If the IP address could not be resolved, the textual representation in a dotted-quad-notation is returned.

Returns
  • the corresponding string name of this IP address.

public static InetAddress getLocalHost ()

Gets the local host address if the security policy allows this. Otherwise, gets the loopback address which allows this machine to be contacted.

The current implementation returns always the loopback address.

Returns
  • the InetAddress representing the local host.
Throws
UnknownHostException if the address lookup fails.

public int hashCode ()

Gets the hashcode of the represented IP address.

Returns
  • the appropriate hashcode value.

public boolean isAnyLocalAddress ()

Returns whether this is a wildcard address or not. This implementation returns always false.

Returns
  • true if this instance represents a wildcard address, false otherwise.

public boolean isLinkLocalAddress ()

Returns whether this address is a link-local address or not. This implementation returns always false.

Valid IPv6 link-local addresses are FE80::0 through to FEBF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF.

There are no valid IPv4 link-local addresses.

Returns
  • true if this instance represents a link-local address, false otherwise.

public boolean isLoopbackAddress ()

Returns whether this address is a loopback address or not. This implementation returns always false. Valid IPv4 loopback addresses are 127.d.d.d The only valid IPv6 loopback address is ::1.

Returns
  • true if this instance represents a loopback address, false otherwise.

public boolean isMCGlobal ()

Returns whether this address is a global multicast address or not. This implementation returns always false.

Valid IPv6 link-global multicast addresses are FFxE:/112 where x is a set of flags, and the additional 112 bits make up the global multicast address space.

Valid IPv4 global multicast addresses are between: 224.0.1.0 to 238.255.255.255.

Returns
  • true if this instance represents a global multicast address, false otherwise.

public boolean isMCLinkLocal ()

Returns whether this address is a link-local multicast address or not. This implementation returns always false.

Valid IPv6 link-local multicast addresses are FFx2:/112 where x is a set of flags, and the additional 112 bits make up the link-local multicast address space.

Valid IPv4 link-local addresses are between: 224.0.0.0 to 224.0.0.255

Returns
  • true if this instance represents a link-local multicast address, false otherwise.

public boolean isMCNodeLocal ()

Returns whether this address is a node-local multicast address or not. This implementation returns always false.

Valid IPv6 node-local multicast addresses are FFx1:/112 where x is a set of flags, and the additional 112 bits make up the node-local multicast address space.

There are no valid IPv4 node-local multicast addresses.

Returns
  • true if this instance represents a node-local multicast address, false otherwise.

public boolean isMCOrgLocal ()

Returns whether this address is a organization-local multicast address or not. This implementation returns always false.

Valid IPv6 organization-local multicast addresses are FFx8:/112 where x is a set of flags, and the additional 112 bits make up the organization-local multicast address space.

Valid IPv4 organization-local addresses are between: 239.192.0.0 to 239.251.255.255

Returns
  • true if this instance represents a organization-local multicast address, false otherwise.

public boolean isMCSiteLocal ()

Returns whether this address is a site-local multicast address or not. This implementation returns always false.

Valid IPv6 site-local multicast addresses are FFx5:/112 where x is a set of flags, and the additional 112 bits make up the site-local multicast address space.

Valid IPv4 site-local addresses are between: 239.252.0.0 to 239.255.255.255

Returns
  • true if this instance represents a site-local multicast address, false otherwise.

public boolean isMulticastAddress ()

Returns whether this address is an IP multicast address or not.

Returns
  • true if this address is in the multicast group, false otherwise.

public boolean isReachable (int timeout)

Tries to reach this InetAddress. This method first tries to use ICMP (ICMP ECHO REQUEST). When first step fails, a TCP connection on port 7 (Echo) of the remote host is established.

Parameters
timeout timeout in milliseconds before the test fails if no connection could be established.
Returns
  • true if this address is reachable, false otherwise.
Throws
IOException if an error occurs during an I/O operation.
IllegalArgumentException if timeout is less than zero.

public boolean isReachable (NetworkInterface netif, int ttl, int timeout)

Tries to reach this InetAddress. This method first tries to use ICMP (ICMP ECHO REQUEST). When first step fails, a TCP connection on port 7 (Echo) of the remote host is established.

Parameters
netif the network interface on which to connection should be established.
ttl the maximum count of hops (time-to-live).
timeout timeout in milliseconds before the test fails if no connection could be established.
Returns
  • true if this address is reachable, false otherwise.
Throws
IOException if an error occurs during an I/O operation.
IllegalArgumentException if ttl or timeout is less than zero.

public boolean isSiteLocalAddress ()

Returns whether this address is a site-local address or not. This implementation returns always false.

Valid IPv6 site-local addresses are FEC0::0 through to FEFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF.

There are no valid IPv4 site-local addresses.

Returns
  • true if this instance represents a site-local address, false otherwise.

public String toString ()

Returns a string containing a concise, human-readable description of this IP address.

Returns
  • the description, as host/address.