Summary: Methods | Inherited Methods | [Expand All]

public class

InetAddress

extends Object
implements Serializable

java.lang.Object
↳	java.net.InetAddress

Known Direct Subclasses

Inet4Address, Inet6Address

Class Overview

An Internet Protocol (IP) address. This can be either an IPv4 address or an IPv6 address, and in practice you'll have an instance of either Inet4Address or Inet6Address (this class cannot be instantiated directly). Most code does not need to distinguish between the two families, and should use InetAddress.

An InetAddress may have a hostname (accessible via getHostName), but may not, depending on how the InetAddress was created.

IPv4 numeric address formats

The getAllByName method accepts IPv4 addresses in the "decimal-dotted-quad" form only:

"1.2.3.4" - 1.2.3.4

IPv6 numeric address formats

The getAllByName method accepts IPv6 addresses in the following forms (this text comes from RFC 2373, which you should consult for full details of IPv6 addressing):

The preferred form is x:x:x:x:x:x:x:x, where the 'x's are the hexadecimal values of the eight 16-bit pieces of the address. Note that it is not necessary to write the leading zeros in an individual field, but there must be at least one numeral in every field (except for the case described in the next bullet). Examples:
```
     FEDC:BA98:7654:3210:FEDC:BA98:7654:3210
     1080:0:0:0:8:800:200C:417A
```
Due to some methods of allocating certain styles of IPv6 addresses, it will be common for addresses to contain long strings of zero bits. In order to make writing addresses containing zero bits easier a special syntax is available to compress the zeros. The use of "::" indicates multiple groups of 16-bits of zeros. The "::" can only appear once in an address. The "::" can also be used to compress the leading and/or trailing zeros in an address. For example the following addresses:
```
     1080:0:0:0:8:800:200C:417A  a unicast address
     FF01:0:0:0:0:0:0:101        a multicast address
     0:0:0:0:0:0:0:1             the loopback address
     0:0:0:0:0:0:0:0             the unspecified addresses
```
may be represented as:
```
     1080::8:800:200C:417A       a unicast address
     FF01::101                   a multicast address
     ::1                         the loopback address
     ::                          the unspecified addresses
```
An alternative form that is sometimes more convenient when dealing with a mixed environment of IPv4 and IPv6 nodes is x:x:x:x:x:x:d.d.d.d, where the 'x's are the hexadecimal values of the six high-order 16-bit pieces of the address, and the 'd's are the decimal values of the four low-order 8-bit pieces of the address (standard IPv4 representation). Examples:
```
     0:0:0:0:0:0:13.1.68.3
     0:0:0:0:0:FFFF:129.144.52.38
```
or in compressed form:
```
     ::13.1.68.3
     ::FFFF:129.144.52.38
```

Scopes are given using a trailing % followed by the scope id, as in 1080::8:800:200C:417A%2 or 1080::8:800:200C:417A%en0. See RFC 4007 for more on IPv6's scoped address architecture.

Additionally, for backwards compatibility, IPv6 addresses may be surrounded by square brackets.

DNS caching

On Android, addresses are cached for 600 seconds (10 minutes) by default. Failed lookups are cached for 10 seconds. The underlying C library or OS may cache for longer, but you can control the Java-level caching with the usual "networkaddress.cache.ttl" and "networkaddress.cache.negative.ttl" system properties. These are parsed as integer numbers of seconds, where the special value 0 means "don't cache" and -1 means "cache forever".

Note also that on Android – unlike the RI – the cache is not unbounded. The current implementation caches around 512 entries, removed on a least-recently-used basis. (Obviously, you should not rely on these details.)

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 literal IP address.
static InetAddress	getByAddress(byte[] ipAddress) Equivalent to `getByAddress(null, ipAddress)`.
static InetAddress	getByAddress(String hostName, byte[] ipAddress) Returns an `InetAddress` corresponding to the given network-order bytes `ipAddress` and `scopeId`.
static InetAddress	getByName(String host) Returns the address of a host according to the given host string name `host`.
String	getCanonicalHostName() Returns the fully qualified hostname corresponding to this IP address.
String	getHostAddress() Returns the numeric representation of this IP address (such as "127.0.0.1").
String	getHostName() Returns the host name corresponding to this IP address.
static InetAddress	getLocalHost() Returns an `InetAddress` for the local host if possible, or the loopback address otherwise.
int	hashCode() Gets the hashcode of the represented IP address.
boolean	isAnyLocalAddress() Returns whether this is the IPv6 unspecified wildcard address `::` or the IPv4 "any" address, `0.0.0.0`.
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 a multicast address or not.
boolean	isReachable(int timeout) Tries to reach this `InetAddress`.
boolean	isReachable(NetworkInterface networkInterface, 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

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of `Class` that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.

IOException	if an error occurs during an I/O operation.
IllegalArgumentException	if timeout is less than zero.

networkInterface	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.

Interfaces

Classes

Enums

Exceptions

InetAddress

Class Overview

IPv4 numeric address formats

IPv6 numeric address formats

DNS caching

See Also

Summary

Public Methods

public boolean equals (Object obj)

Parameters

Returns

public byte[] getAddress ()

Returns

public static InetAddress[] getAllByName (String host)

Parameters

Returns

Throws

public static InetAddress getByAddress (byte[] ipAddress)

Throws

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

Throws

public static InetAddress getByName (String host)

Parameters

Returns

Throws

public String getCanonicalHostName ()

public String getHostAddress ()

public String getHostName ()

public static InetAddress getLocalHost ()

Returns

Throws

public int hashCode ()

Returns

public boolean isAnyLocalAddress ()

public boolean isLinkLocalAddress ()

public boolean isLoopbackAddress ()

public boolean isMCGlobal ()

public boolean isMCLinkLocal ()

public boolean isMCNodeLocal ()

public boolean isMCOrgLocal ()

public boolean isMCSiteLocal ()

public boolean isMulticastAddress ()

public boolean isReachable (int timeout)

Parameters

Returns

Throws

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

Parameters

Returns

Throws

public boolean isSiteLocalAddress ()

Returns

public String toString ()

Returns