Class Inet4Address

java.lang.Object
java.net.InetAddress
java.net.Inet4Address
All Implemented Interfaces:
Serializable
public final classInet4AddressextendsInetAddress
This class represents an Internet Protocol version 4 (IPv4) address. Defined byRFC 790: Assigned Numbers,RFC 1918: Address Allocation for Private Internets, andRFC 2365: Administratively Scoped IP Multicast

Textual representation of IPv4 addresses

Textual representation of IPv4 address used as input to methods takes one of the following forms:
  • d.d.d.d
  • d.d.d
  • d.d
  • d

When four parts are specified, each is interpreted as a byte of data and assigned, from left to right, to the four bytes of an IPv4 address.

When a three part address is specified, the last part is interpreted as a 16-bit quantity and placed in the right most two bytes of the network address. This makes the three part address format convenient for specifying Class B network addresses as 128.net.host.

When a two part address is supplied, the last part is interpreted as a 24-bit quantity and placed in the right most three bytes of the network address. This makes the two part address format convenient for specifying Class A network addresses as net.host.

When only one part is given, the value is stored directly in the network address without any byte rearrangement.

For example, the following (decimal) forms are supported by the methodsofLiteral(String) andInetAddress.getByName(String) which are capable of parsing textual representations of IPv4 addresses:

 // Dotted-decimal 'd.d.d.d' form with four part address literal InetAddress.getByName("007.008.009.010"); // ==> /7.8.9.10 InetAddress.getByName("127.0.1.1");       // ==> /127.0.1.1 // Dotted-decimal 'd.d.d' form with three part address literal, // the last part is placed in the right most two bytes // of the constructed address InetAddress.getByName("127.0.257"); // ==> /127.0.1.1 // Dotted-decimal 'd.d' form with two part address literal, // the last part is placed in the right most three bytes // of the constructed address Inet4Address.ofLiteral("127.257"); // ==> /127.0.1.1 // 'd' form with one decimal value that is stored directly in // the constructed address bytes without any rearrangement Inet4Address.ofLiteral("02130706689"); // ==> /127.0.1.1

The above forms adhere to "strict" decimal-only syntax. Additionally, theofPosixLiteral(String) method implements a POSIXinet_addr compatible "loose" parsing algorithm, allowing octal and hexadecimal address segments. Please refer toRFC 6943: Issues in Identifier Comparison for Security Purposes. Aside fromInet4Address.ofPosixLiteral(String), all methods only support strict decimal parsing.

For methods that return a textual representation as output value, the first form, i.e. a dotted-quad string in strict decimal notation, is used.

The Scope of a Multicast Address

Historically the IPv4 TTL field in the IP header has doubled as a multicast scope field: a TTL of 0 means node-local, 1 means link-local, up through 32 means site-local, up through 64 means region-local, up through 128 means continent-local, and up through 255 are global. However, the administrative scoping is preferred. Please refer toRFC 2365: Administratively Scoped IP Multicast
Since:
1.4
External Specifications
See Also:

  • Method Details

    • ofLiteral

      public static Inet4Address ofLiteral(String ipv4AddressLiteral)
      Creates anInet4Address based on the providedtextual representation of an IPv4 address.

      If the provided IPv4 address literal cannot represent avalid IPv4 address anIllegalArgumentException is thrown.

      This method doesn't block, i.e. no reverse lookup is performed.

      Parameters:
      ipv4AddressLiteral - the textual representation of an IPv4 address.
      Returns:
      anInet4Address object with no hostname set, and constructed from the provided IPv4 address literal.
      Throws:
      IllegalArgumentException - if theipv4AddressLiteral cannot be parsed as an IPv4 address literal.
      NullPointerException - if theipv4AddressLiteral isnull.
      Since:
      22

    • ofPosixLiteral

      public static Inet4Address ofPosixLiteral(String posixIPAddressLiteral)
      Creates anInet4Address based on the providedtextual representation of an IPv4 address in POSIXinet_addr compatible form.

      The methodofPosixLiteral implements POSIXinet_addr compatible parsing algorithm, allowing octal and hexadecimal address segments."0" is the prefix for octal numbers,"0x" and"0X" are the prefixes for hexadecimal numbers. Non-zero address segments that start from non-zero digits are parsed as decimal numbers. The following (non-decimal) forms are supported by this method:

       // Dotted-quad 'x.x.x.x' form with four part address literal Inet4Address.ofPosixLiteral("0177.0.0.1"); // ==> /127.0.0.1 Inet4Address.ofPosixLiteral("0x7F.0.0.1"); // ==> /127.0.0.1 // Dotted-triple 'x.x.x' form with three part address literal, // the last part is placed in the rightmost two bytes // of the constructed address Inet4Address.ofPosixLiteral("0177.0.0402"); // ==> /127.0.1.2 Inet4Address.ofPosixLiteral("0x7F.0.0x102"); // ==> /127.0.1.2 // Dotted-double 'x.x' form with two part address literal, // the last part is placed in the rightmost three bytes // of the constructed address Inet4Address.ofPosixLiteral("0177.0201003"); // ==> /127.1.2.3 Inet4Address.ofPosixLiteral("0x7F.0x10203"); // ==> /127.1.2.3 Inet4Address.ofPosixLiteral("127.66051"); // ==> /127.1.2.3 // Dotless 'x' form with one value that is stored directly in // the constructed address bytes without any rearrangement Inet4Address.ofPosixLiteral("0100401404"); // ==> /1.2.3.4 Inet4Address.ofPosixLiteral("0x1020304"); // ==> /1.2.3.4 Inet4Address.ofPosixLiteral("16909060"); // ==> /1.2.3.4

      If the provided IPv4 address literal cannot represent a valid IPv4 address inPOSIX form anIllegalArgumentException is thrown.

      This method doesn't block, i.e. no hostname lookup is performed.

      API Note:
      This method produces different results compared toofLiteral(java.lang.String) whenposixIPAddressLiteral parameter contains address segments with leading zeroes. An address segment with a leading zero is always parsed as an octal number by this method, therefore0255 (octal) will be parsed as173 (decimal). On the other hand,Inet4Address.ofLiteral ignores leading zeros, parses all numbers as decimal and produces255. Where this method would parse0256.0256.0256.0256 (octal) and produce174.174.174.174 (decimal) in four dotted quad notation,Inet4Address.ofLiteral will throwIllegalArgumentException.
      Parameters:
      posixIPAddressLiteral - a textual representation of an IPv4 address.
      Returns:
      anInet4Address object with no hostname set, and constructed from the provided IPv4 address literal.
      Throws:
      IllegalArgumentException - if theposixIPAddressLiteral cannot be parsed as an IPv4 address literal.
      NullPointerException - if theposixIPAddressLiteral isnull.
      Since:
      23

    • isMulticastAddress

      public boolean isMulticastAddress()
      Utility routine to check if the InetAddress is an IP multicast address. IP multicast address is a Class D address i.e first four bits of the address are 1110.
      Overrides:
      isMulticastAddress in class InetAddress
      Returns:
      aboolean indicating if the InetAddress is an IP multicast address

    • isAnyLocalAddress

      public boolean isAnyLocalAddress()
      Utility routine to check if the InetAddress is a wildcard address.
      Overrides:
      isAnyLocalAddress in class InetAddress
      Returns:
      aboolean indicating if the InetAddress is a wildcard address.

    • isLoopbackAddress

      public boolean isLoopbackAddress()
      Utility routine to check if the InetAddress is a loopback address.
      Overrides:
      isLoopbackAddress in class InetAddress
      Returns:
      aboolean indicating if the InetAddress is a loopback address; or false otherwise.

    • isLinkLocalAddress

      public boolean isLinkLocalAddress()
      Utility routine to check if the InetAddress is a link local address.
      Overrides:
      isLinkLocalAddress in class InetAddress
      Returns:
      aboolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.

    • isSiteLocalAddress

      public boolean isSiteLocalAddress()
      Utility routine to check if the InetAddress is a site local address.
      Overrides:
      isSiteLocalAddress in class InetAddress
      Returns:
      aboolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.

    • isMCGlobal

      public boolean isMCGlobal()
      Utility routine to check if the multicast address has global scope.
      Overrides:
      isMCGlobal in class InetAddress
      Returns:
      aboolean indicating if the address has is a multicast address of global scope, false if it is not of global scope or it is not a multicast address

    • isMCNodeLocal

      public boolean isMCNodeLocal()
      Utility routine to check if the multicast address has node scope.
      Overrides:
      isMCNodeLocal in class InetAddress
      Returns:
      aboolean indicating if the address has is a multicast address of node-local scope, false if it is not of node-local scope or it is not a multicast address

    • isMCLinkLocal

      public boolean isMCLinkLocal()
      Utility routine to check if the multicast address has link scope.
      Overrides:
      isMCLinkLocal in class InetAddress
      Returns:
      aboolean indicating if the address has is a multicast address of link-local scope, false if it is not of link-local scope or it is not a multicast address

    • isMCSiteLocal

      public boolean isMCSiteLocal()
      Utility routine to check if the multicast address has site scope.
      Overrides:
      isMCSiteLocal in class InetAddress
      Returns:
      aboolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address

    • isMCOrgLocal

      public boolean isMCOrgLocal()
      Utility routine to check if the multicast address has organization scope.
      Overrides:
      isMCOrgLocal in class InetAddress
      Returns:
      aboolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address

    • getAddress

      public byte[] getAddress()
      Returns the raw IP address of thisInetAddress object. The result is in network byte order: the highest order byte of the address is ingetAddress()[0].
      Overrides:
      getAddress in class InetAddress
      Returns:
      the raw IP address of this object.

    • getHostAddress

      public String getHostAddress()
      Returns the IP address string in textual presentation form.
      Overrides:
      getHostAddress in class InetAddress
      Returns:
      the raw IP address in a string format.

    • hashCode

      public int hashCode()
      Returns a hashcode for this IP address.
      Overrides:
      hashCode in class InetAddress
      Returns:
      a hash code value for this IP address.
      See Also:

    • equals

      public boolean equals(Object obj)
      Compares this object against the specified object. The result istrue if and only if the argument is notnull and it represents the same IP address as this object.

      Two instances ofInetAddress represent the same IP address if the length of the byte arrays returned bygetAddress is the same for both, and each of the array components is the same for the byte arrays.

      Overrides:
      equals in class InetAddress
      Parameters:
      obj - the object to compare against.
      Returns:
      true if the objects are the same;false otherwise.
      See Also: