The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address. If a literal IP address is supplied, only the validity of the address format is checked.

For host specified in literal IPv6 address, either the form defined in RFC 2732 or the literal IPv6 address format defined in RFC 2373 is accepted. A literal IPv6 address may also be qualified by appending a scoped zone identifier or scope_id. The syntax and usage of scope_ids is described here.

If the host is null then an InetAddress representing an address of the loopback interface is returned. See RFC 3330 section 2 and RFC 2373 section 2.5.3.

If there is a security manager and host is not null and host.length() is not equal to zero, the security manager's checkConnect method is called with the hostname and -1 as its arguments to see if the operation is allowed.
Returns: an array of all the IP addresses for a given host name.
Parameters:
- host - the name of the host, or null.
Throws:
- UnknownHostException - if no IP address for the host could be found, or if a scope_id was specified for a global IPv6 address.
- SecurityException - if a security manager exists and its checkConnect method doesn't allow the operation.
See Also: SecurityManager.checkConnect(java.lang.String, int),

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

IPv4 address byte array must be 4 bytes long and IPv6 byte array must be 16 bytes long
Returns: an InetAddress object created from the raw IP address.
Parameters:
- addr - the raw IP address in network byte order
Throws:
- UnknownHostException - if IP address is of illegal length
Since: 1.4

The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address.

No validity checking is done on the host name either.

If addr specifies an IPv4 address an instance of Inet4Address will be returned; otherwise, an instance of Inet6Address will be returned.

IPv4 address byte array must be 4 bytes long and IPv6 byte array must be 16 bytes long
Returns: an InetAddress object created from the raw IP address.
Parameters:
- host - the specified host
- addr - the raw IP address in network byte order
Throws:
- UnknownHostException - if IP address is of illegal length
Since: 1.4

The host name can either be a machine name, such as "java.sun.com", or a textual representation of its IP address. If a literal IP address is supplied, only the validity of the address format is checked.

For host specified in literal IPv6 address, either the form defined in RFC 2732 or the literal IPv6 address format defined in RFC 2373 is accepted. IPv6 scoped addresses are also supported. See here for a description of IPv6 scoped addresses.

If the host is null then an InetAddress representing an address of the loopback interface is returned. See RFC 3330 section 2 and RFC 2373 section 2.5.3.

If there is a security manager, this method first calls its checkConnect method with the hostname and -1 as its arguments to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. If the operation is not allowed, it will return the textual representation of the IP address.
Returns: the fully qualified domain name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
Since: 1.4
See Also: SecurityManager.checkConnect(java.lang.String, int),

If this InetAddress was created with a host name, this host name will be remembered and returned; otherwise, a reverse name lookup will be performed and the result will be returned based on the system configured name lookup service. If a lookup of the name service is required, call getCanonicalHostName.

If there is a security manager, its checkConnect method is first called with the hostname and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, it will return the textual representation of the IP address.
Returns: the host name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
See Also: InetAddress.getCanonicalHostName(), SecurityManager.checkConnect(java.lang.String, int),

If there is a security manager, this method first calls its checkConnect method with the hostname and -1 as its arguments to see if the calling code is allowed to know the hostname for this IP address, i.e., to connect to the host. If the operation is not allowed, it will return the textual representation of the IP address.
Returns: the host name for this IP address, or if the operation is not allowed by the security check, the textual representation of the IP address.
Parameters:
- check - make security check if true
See Also: SecurityManager.checkConnect(java.lang.String, int),

If there is a security manager, its checkConnect method is called with the local host name and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, an InetAddress representing the loopback address is returned.
Returns: the IP address of the local host.
Throws:
- UnknownHostException - if no IP address for the host could be found.
See Also: SecurityManager.checkConnect(java.lang.String, int),

The timeout value, in milliseconds, indicates the maximum amount of time the try should take. If the operation times out before getting an answer, the host is deemed unreachable. A negative value will result in an IllegalArgumentException being thrown.
Returns: a boolean indicating if the address is reachable.
Parameters:
- timeout - the time, in milliseconds, before the call aborts
Throws:
- IOException - if a network error occurs
- IllegalArgumentException - if timeout is negative.
Since: 1.5

The network interface and ttl parameters let the caller specify which network interface the test will go through and the maximum number of hops the packets should go through. A negative value for the ttl will result in an IllegalArgumentException being thrown.

The timeout value, in milliseconds, indicates the maximum amount of time the try should take. If the operation times out before getting an answer, the host is deemed unreachable. A negative value will result in an IllegalArgumentException being thrown.
Returns: a booleanindicating if the address is reachable.
Parameters:
- netif - the NetworkInterface through which the test will be done, or null for any interface
- ttl - the maximum numbers of hops to try or 0 for the default
- timeout - the time, in milliseconds, before the call aborts
Throws:
- IllegalArgumentException - if either timeout or ttl are negative.
- IOException - if a network error occurs
Since: 1.5