InetSocketAddress (Java SE 22 & JDK 22)
Description: declaration: module: java.base, package: java.net, class: InetSocketAddress
Keywords: java.net.InetSocketAddress class

Module java.base
Package java.net

# Class InetSocketAddress

java.lang.Object
java.net.SocketAddress
java.net.InetSocketAddress

All Implemented Interfaces:
  `Serializable`

public class InetSocketAddress extends SocketAddress
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. If resolution fails then the address is said to be unresolved but can still be used on some circumstances like connecting through a proxy.

It provides an immutable object used by sockets for binding, connecting, or as returned values.

The wildcard is a special local IP address. It usually means "any" and can only be used for `bind` operations.

Since:
  1.4
See Also:
  - `Socket`
  - `ServerSocket`
  - Serialized Form

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `InetSocketAddress(int port)`
  Creates a socket address where the IP address is the wildcard address and the port number a specified value.
  `InetSocketAddress(String hostname, int port)`
  Creates a socket address from a hostname and a port number.
  `InetSocketAddress(InetAddress addr, int port)`
  Creates a socket address from an IP address and a port number.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static InetSocketAddress`
  `createUnresolved(String host, int port)`
  Creates an unresolved socket address from a hostname and a port number.
  `final boolean`
  `equals(Object obj)`
  Compares this object against the specified object.
  `final InetAddress`
  `getAddress()`
  Gets the `InetAddress`.
  `final String`
  `getHostName()`
  Gets the `hostname`.
  `final String`
  `getHostString()`
  Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal).
  `final int`
  `getPort()`
  Gets the port number.
  `final int`
  `hashCode()`
  Returns a hashcode for this socket address.
  `final boolean`
  `isUnresolved()`
  Checks whether the address has been resolved or not.
  `String`
  `toString()`
  Constructs a string representation of this InetSocketAddress.

  ### Methods declared in class java.lang.Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- ## Constructor Details

  - ### InetSocketAddress

    public InetSocketAddress(int port)
    Creates a socket address where the IP address is the wildcard address and the port number a specified value.

    A valid port value is between 0 and 65535. A port number of `zero` will let the system pick up an ephemeral port in a `bind` operation.

    Parameters:
      `port` - The port number
    Throws:
      `IllegalArgumentException` - if the port parameter is outside the specified range of valid port values.

  - ### InetSocketAddress

    public InetSocketAddress(InetAddress addr, int port)
    Creates a socket address from an IP address and a port number.

    A valid port value is between 0 and 65535. A port number of `zero` will let the system pick up an ephemeral port in a `bind` operation.

    A `null` address will assign the wildcard address.

    Parameters:
      `addr` - The IP address
      `port` - The port number
    Throws:
      `IllegalArgumentException` - if the port parameter is outside the specified range of valid port values.

  - ### InetSocketAddress

    public InetSocketAddress(String hostname, int port)
    Creates a socket address from a hostname and a port number.

    An attempt will be made to resolve the hostname into an InetAddress. If that attempt fails, the address will be flagged as unresolved.

    If there is a security manager, its `checkConnect` method is called with the host name as its argument to check the permission to resolve it. This could result in a SecurityException.

    A valid port value is between 0 and 65535. A port number of `zero` will let the system pick up an ephemeral port in a `bind` operation.

    Parameters:
      `hostname` - the Host name
      `port` - The port number
    Throws:
      `IllegalArgumentException` - if the port parameter is outside the range of valid port values, or if the hostname parameter is `null`.
      `SecurityException` - if a security manager is present and permission to resolve the host name is denied.
    See Also:
      - `isUnresolved()`

- ## Method Details

  - ### createUnresolved

    public static InetSocketAddress createUnresolved(String host, int port)
    Creates an unresolved socket address from a hostname and a port number.

    No attempt will be made to resolve the hostname into an InetAddress. The address will be flagged as unresolved.

    A valid port value is between 0 and 65535. A port number of `zero` will let the system pick up an ephemeral port in a `bind` operation.

    Parameters:
      `host` - the Host name
      `port` - The port number
    Returns:
      an `InetSocketAddress` representing the unresolved socket address
    Throws:
      `IllegalArgumentException` - if the port parameter is outside the range of valid port values, or if the hostname parameter is `null`.
    Since:
      1.5
    See Also:
      - `isUnresolved()`

  - ### getPort

    public final int getPort()
    Gets the port number.
    Returns:
      the port number.

  - ### getAddress

    public final InetAddress getAddress()
    Gets the `InetAddress`.
    Returns:
      the InetAddress or `null` if it is unresolved.

  - ### getHostName

    public final String getHostName()
    Gets the `hostname`. Note: This method may trigger a name service reverse lookup if the address was created with a literal IP address.
    Returns:
      the hostname part of the address.

  - ### getHostString

    public final String getHostString()
    Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal). This has the benefit of not attempting a reverse lookup.
    Returns:
      the hostname, or String representation of the address.
    Since:
      1.7

  - ### isUnresolved

    public final boolean isUnresolved()
    Checks whether the address has been resolved or not.
    Returns:
      `true` if the hostname couldn't be resolved into an `InetAddress`.

  - ### toString

    public String toString()
    Constructs a string representation of this InetSocketAddress. This string is constructed by calling `InetAddress.toString()` on the InetAddress and concatenating the port number (with a colon).

    If the address is an IPv6 address, the IPv6 literal is enclosed in square brackets, for example: `"localhost/[0:0:0:0:0:0:0:1]:80"`. If the address is unresolved, `<unresolved>` is displayed in place of the address literal, for example `"foo/<unresolved>:80"`.

    To retrieve a string representation of the hostname or the address, use `getHostString()`, rather than parsing the string returned by this `toString()` method.

    Overrides:
      `toString` in class `Object`
    Returns:
      a string representation of this object.

  - ### equals

    public final boolean equals(Object obj)
    Compares this object against the specified object. The result is `true` if and only if the argument is not `null` and it represents the same address as this object.

    Two instances of `InetSocketAddress` represent the same address if both the InetAddresses (or hostnames if it is unresolved) and port numbers are equal. If both addresses are unresolved, then the hostname and the port number are compared. Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are considered equal.

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

  - ### hashCode

    public final int hashCode()
    Returns a hashcode for this socket address.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      a hash code value for this socket address.
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(java.lang.Object)`