java/11 : java.base/java/net/NetworkInterface.java

NetworkInterface
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 *
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package java.net;

import java.util.Arrays;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import java.security.AccessController;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

This class represents a Network Interface made up of a name,
and a list of IP addresses assigned to this interface.
It is used to identify the local interface on which a multicast group
is joined.
Interfaces are normally known by names such as "le0".
Since: 1.4/**
 * This class represents a Network Interface made up of a name,
 * and a list of IP addresses assigned to this interface.
 * It is used to identify the local interface on which a multicast group
 * is joined.
 *
 * Interfaces are normally known by names such as "le0".
 *
 * @since 1.4
 */
public final class NetworkInterface {
    private String name;
    private String displayName;
    private int index;
    private InetAddress addrs[];
    private InterfaceAddress bindings[];
    private NetworkInterface childs[];
    private NetworkInterface parent = null;
    private boolean virtual = false;
    private static final NetworkInterface defaultInterface;
    private static final int defaultIndex; /* index of defaultInterface */

    static {
        AccessController.doPrivileged(
            new java.security.PrivilegedAction<>() {
                public Void run() {
                    System.loadLibrary("net");
                    return null;
                }
            });

        init();
        defaultInterface = DefaultInterface.getDefault();
        if (defaultInterface != null) {
            defaultIndex = defaultInterface.getIndex();
        } else {
            defaultIndex = 0;
        }
    }

    Returns an NetworkInterface object with index set to 0 and name to null.
Setting such an interface on a MulticastSocket will cause the
kernel to choose one interface for sending multicast packets.
/**
     * Returns an NetworkInterface object with index set to 0 and name to null.
     * Setting such an interface on a MulticastSocket will cause the
     * kernel to choose one interface for sending multicast packets.
     *
     */
    NetworkInterface() {
    }

    NetworkInterface(String name, int index, InetAddress[] addrs) {
        this.name = name;
        this.index = index;
        this.addrs = addrs;
    }

    Get the name of this network interface.
Returns: the name of this network interface/**
     * Get the name of this network interface.
     *
     * @return the name of this network interface
     */
    public String getName() {
            return name;
    }

    Get an Enumeration with all or a subset of the InetAddresses bound to
this network interface.
 If there is a security manager, its checkConnect method is called for each InetAddress. Only InetAddresses where the checkConnect doesn't throw a SecurityException will be returned in the Enumeration. However, if the caller has the NetPermission("getNetworkInformation") permission, then all InetAddresses are returned. 
See Also: inetAddresses()
Returns: an Enumeration object with all or a subset of the InetAddresses
bound to this network interface/**
     * Get an Enumeration with all or a subset of the InetAddresses bound to
     * this network interface.
     * <p>
     * If there is a security manager, its {@code checkConnect}
     * method is called for each InetAddress. Only InetAddresses where
     * the {@code checkConnect} doesn't throw a SecurityException
     * will be returned in the Enumeration. However, if the caller has the
     * {@link NetPermission}("getNetworkInformation") permission, then all
     * InetAddresses are returned.
     *
     * @return an Enumeration object with all or a subset of the InetAddresses
     * bound to this network interface
     * @see #inetAddresses()
     */
    public Enumeration<InetAddress> getInetAddresses() {
        return enumerationFromArray(getCheckedInetAddresses());
    }

    Get a Stream of all or a subset of the InetAddresses bound to this
network interface.
 If there is a security manager, its checkConnect method is called for each InetAddress. Only InetAddresses where the checkConnect doesn't throw a SecurityException will be returned in the Stream. However, if the caller has the NetPermission("getNetworkInformation") permission, then all InetAddresses are returned. 
Returns: a Stream object with all or a subset of the InetAddresses
bound to this network interface
Since: 9/**
     * Get a Stream of all or a subset of the InetAddresses bound to this
     * network interface.
     * <p>
     * If there is a security manager, its {@code checkConnect}
     * method is called for each InetAddress. Only InetAddresses where
     * the {@code checkConnect} doesn't throw a SecurityException will be
     * returned in the Stream. However, if the caller has the
     * {@link NetPermission}("getNetworkInformation") permission, then all
     * InetAddresses are returned.
     *
     * @return a Stream object with all or a subset of the InetAddresses
     * bound to this network interface
     * @since 9
     */
    public Stream<InetAddress> inetAddresses() {
        return streamFromArray(getCheckedInetAddresses());
    }

    private InetAddress[] getCheckedInetAddresses() {
        InetAddress[] local_addrs = new InetAddress[addrs.length];
        boolean trusted = true;

        SecurityManager sec = System.getSecurityManager();
        if (sec != null) {
            try {
                sec.checkPermission(new NetPermission("getNetworkInformation"));
            } catch (SecurityException e) {
                trusted = false;
            }
        }
        int i = 0;
        for (int j = 0; j < addrs.length; j++) {
            try {
                if (!trusted) {
                    sec.checkConnect(addrs[j].getHostAddress(), -1);
                }
                local_addrs[i++] = addrs[j];
            } catch (SecurityException e) { }
        }
        return Arrays.copyOf(local_addrs, i);
    }

    Get a List of all or a subset of the InterfaceAddresses of this network interface.  If there is a security manager, its checkConnect method is called with the InetAddress for each InterfaceAddress. Only InterfaceAddresses where the checkConnect doesn't throw a SecurityException will be returned in the List. 
Returns: a List object with all or a subset of the InterfaceAddresss of this network interface
Since: 1.6/**
     * Get a List of all or a subset of the {@code InterfaceAddresses}
     * of this network interface.
     * <p>
     * If there is a security manager, its {@code checkConnect}
     * method is called with the InetAddress for each InterfaceAddress.
     * Only InterfaceAddresses where the {@code checkConnect} doesn't throw
     * a SecurityException will be returned in the List.
     *
     * @return a {@code List} object with all or a subset of the
     *         InterfaceAddresss of this network interface
     * @since 1.6
     */
    public java.util.List<InterfaceAddress> getInterfaceAddresses() {
        java.util.List<InterfaceAddress> lst = new java.util.ArrayList<>(1);
        if (bindings != null) {
            SecurityManager sec = System.getSecurityManager();
            for (int j=0; j<bindings.length; j++) {
                try {
                    if (sec != null) {
                        sec.checkConnect(bindings[j].getAddress().getHostAddress(), -1);
                    }
                    lst.add(bindings[j]);
                } catch (SecurityException e) { }
            }
        }
        return lst;
    }

    Get an Enumeration with all the subinterfaces (also known as virtual
interfaces) attached to this network interface.

For instance eth0:1 will be a subinterface to eth0.
See Also: subInterfaces()
Returns: an Enumeration object with all of the subinterfaces
of this network interface
Since: 1.6/**
     * Get an Enumeration with all the subinterfaces (also known as virtual
     * interfaces) attached to this network interface.
     * <p>
     * For instance eth0:1 will be a subinterface to eth0.
     *
     * @return an Enumeration object with all of the subinterfaces
     * of this network interface
     * @see #subInterfaces()
     * @since 1.6
     */
    public Enumeration<NetworkInterface> getSubInterfaces() {
        return enumerationFromArray(childs);
    }

    Get a Stream of all subinterfaces (also known as virtual
interfaces) attached to this network interface.
Returns: a Stream object with all of the subinterfaces
of this network interface
Since: 9/**
     * Get a Stream of all subinterfaces (also known as virtual
     * interfaces) attached to this network interface.
     *
     * @return a Stream object with all of the subinterfaces
     * of this network interface
     * @since 9
     */
    public Stream<NetworkInterface> subInterfaces() {
        return streamFromArray(childs);
    }

    Returns the parent NetworkInterface of this interface if this is a subinterface, or null if it is a physical (non virtual) interface or has no parent. 
Returns: The NetworkInterface this interface is attached to.
Since: 1.6/**
     * Returns the parent NetworkInterface of this interface if this is
     * a subinterface, or {@code null} if it is a physical
     * (non virtual) interface or has no parent.
     *
     * @return The {@code NetworkInterface} this interface is attached to.
     * @since 1.6
     */
    public NetworkInterface getParent() {
        return parent;
    }

    Returns the index of this network interface. The index is an integer greater or equal to zero, or -1 for unknown. This is a system specific value and interfaces with the same name can have different indexes on different machines. 
See Also: getByIndex(int)
Returns: the index of this network interface or -1 if the index is unknown
Since: 1.7/**
     * Returns the index of this network interface. The index is an integer greater
     * or equal to zero, or {@code -1} for unknown. This is a system specific value
     * and interfaces with the same name can have different indexes on different
     * machines.
     *
     * @return the index of this network interface or {@code -1} if the index is
     *         unknown
     * @see #getByIndex(int)
     * @since 1.7
     */
    public int getIndex() {
        return index;
    }

    Get the display name of this network interface.
A display name is a human readable String describing the network
device.
Returns: a non-empty string representing the display name of this network
        interface, or null if no display name is available./**
     * Get the display name of this network interface.
     * A display name is a human readable String describing the network
     * device.
     *
     * @return a non-empty string representing the display name of this network
     *         interface, or null if no display name is available.
     */
    public String getDisplayName() {
        /* strict TCK conformance */
        return "".equals(displayName) ? null : displayName;
    }

    Searches for the network interface with the specified name.
Params: name – 
         The name of the network interface.
Throws: SocketException – 
         If an I/O error occurs.
NullPointerException –  If the specified name is null.
Returns:  A NetworkInterface with the specified name, or null if there is no network interface with the specified name./**
     * Searches for the network interface with the specified name.
     *
     * @param   name
     *          The name of the network interface.
     *
     * @return  A {@code NetworkInterface} with the specified name,
     *          or {@code null} if there is no network interface
     *          with the specified name.
     *
     * @throws  SocketException
     *          If an I/O error occurs.
     *
     * @throws  NullPointerException
     *          If the specified name is {@code null}.
     */
    public static NetworkInterface getByName(String name) throws SocketException {
        if (name == null)
            throw new NullPointerException();
        return getByName0(name);
    }

    Get a network interface given its index.
Params: index – an integer, the index of the interface
Throws: SocketException –  if an I/O error occurs.
IllegalArgumentException – if index has a negative value
See Also: getIndex()
Returns: the NetworkInterface obtained from its index, or null if there is no interface with such an index on the system
Since: 1.7/**
     * Get a network interface given its index.
     *
     * @param index an integer, the index of the interface
     * @return the NetworkInterface obtained from its index, or {@code null} if
     *         there is no interface with such an index on the system
     * @throws  SocketException  if an I/O error occurs.
     * @throws  IllegalArgumentException if index has a negative value
     * @see #getIndex()
     * @since 1.7
     */
    public static NetworkInterface getByIndex(int index) throws SocketException {
        if (index < 0)
            throw new IllegalArgumentException("Interface index can't be negative");
        return getByIndex0(index);
    }

    Convenience method to search for a network interface that
has the specified Internet Protocol (IP) address bound to
it.

If the specified IP address is bound to multiple network
interfaces it is not defined which network interface is
returned.
Params: addr –  The InetAddress to search with.
Throws: SocketException – 
         If an I/O error occurs.
NullPointerException –  If the specified address is null.
Returns:  A NetworkInterface or null if there is no network interface with the specified IP address./**
     * Convenience method to search for a network interface that
     * has the specified Internet Protocol (IP) address bound to
     * it.
     * <p>
     * If the specified IP address is bound to multiple network
     * interfaces it is not defined which network interface is
     * returned.
     *
     * @param   addr
     *          The {@code InetAddress} to search with.
     *
     * @return  A {@code NetworkInterface}
     *          or {@code null} if there is no network interface
     *          with the specified IP address.
     *
     * @throws  SocketException
     *          If an I/O error occurs.
     *
     * @throws  NullPointerException
     *          If the specified address is {@code null}.
     */
    public static NetworkInterface getByInetAddress(InetAddress addr) throws SocketException {
        if (addr == null) {
            throw new NullPointerException();
        }
        if (addr instanceof Inet4Address) {
            Inet4Address inet4Address = (Inet4Address) addr;
            if (inet4Address.holder.family != InetAddress.IPv4) {
                throw new IllegalArgumentException("invalid family type: "
                        + inet4Address.holder.family);
            }
        } else if (addr instanceof Inet6Address) {
            Inet6Address inet6Address = (Inet6Address) addr;
            if (inet6Address.holder.family != InetAddress.IPv6) {
                throw new IllegalArgumentException("invalid family type: "
                        + inet6Address.holder.family);
            }
        } else {
            throw new IllegalArgumentException("invalid address type: " + addr);
        }
        return getByInetAddress0(addr);
    }

    Returns an Enumeration of all the interfaces on this machine. The Enumeration contains at least one element, possibly representing a loopback interface that only supports communication between entities on this machine. 
Throws: SocketException –  if an I/O error occurs,
            or if the platform does not have at least one configured
            network interface.
See Also: networkInterfaces()
API Note: this method can be used in combination with getInetAddresses() to obtain all IP addresses for this node
Returns: an Enumeration of NetworkInterfaces found on this machine/**
     * Returns an {@code Enumeration} of all the interfaces on this machine. The
     * {@code Enumeration} contains at least one element, possibly representing
     * a loopback interface that only supports communication between entities on
     * this machine.
     *
     * @apiNote this method can be used in combination with
     * {@link #getInetAddresses()} to obtain all IP addresses for this node
     *
     * @return an Enumeration of NetworkInterfaces found on this machine
     * @exception  SocketException  if an I/O error occurs,
     *             or if the platform does not have at least one configured
     *             network interface.
     * @see #networkInterfaces()
     */
    public static Enumeration<NetworkInterface> getNetworkInterfaces()
        throws SocketException {
        NetworkInterface[] netifs = getAll();
        if (netifs != null && netifs.length > 0) {
            return enumerationFromArray(netifs);
        } else {
            throw new SocketException("No network interfaces configured");
        }
    }

    Returns a Stream of all the interfaces on this machine. The Stream contains at least one interface, possibly representing a loopback interface that only supports communication between entities on this machine. 
Throws: SocketException –  if an I/O error occurs,
            or if the platform does not have at least one configured
            network interface.
API Note: this method can be used in combination with inetAddresses()} to obtain a stream of all IP addresses for this node, for example:  
Stream<InetAddress> addrs = NetworkInterface.networkInterfaces()
    .flatMap(NetworkInterface::inetAddresses);
Returns: a Stream of NetworkInterfaces found on this machine
Since: 9/**
     * Returns a {@code Stream} of all the interfaces on this machine.  The
     * {@code Stream} contains at least one interface, possibly representing a
     * loopback interface that only supports communication between entities on
     * this machine.
     *
     * @apiNote this method can be used in combination with
     * {@link #inetAddresses()}} to obtain a stream of all IP addresses for
     * this node, for example:
     * <pre> {@code
     * Stream<InetAddress> addrs = NetworkInterface.networkInterfaces()
     *     .flatMap(NetworkInterface::inetAddresses);
     * }</pre>
     *
     * @return a Stream of NetworkInterfaces found on this machine
     * @exception  SocketException  if an I/O error occurs,
     *             or if the platform does not have at least one configured
     *             network interface.
     * @since 9
     */
    public static Stream<NetworkInterface> networkInterfaces()
        throws SocketException {
        NetworkInterface[] netifs = getAll();
        if (netifs != null && netifs.length > 0) {
            return streamFromArray(netifs);
        }  else {
            throw new SocketException("No network interfaces configured");
        }
    }

    private static <T> Enumeration<T> enumerationFromArray(T[] a) {
        return new Enumeration<>() {
            int i = 0;

            @Override
            public T nextElement() {
                if (i < a.length) {
                    return a[i++];
                } else {
                    throw new NoSuchElementException();
                }
            }

            @Override
            public boolean hasMoreElements() {
                return i < a.length;
            }
        };
    }

    private static <T> Stream<T> streamFromArray(T[] a) {
        return StreamSupport.stream(
                Spliterators.spliterator(
                        a,
                        Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL),
                false);
    }

    private static native NetworkInterface[] getAll()
        throws SocketException;

    private static native NetworkInterface getByName0(String name)
        throws SocketException;

    private static native NetworkInterface getByIndex0(int index)
        throws SocketException;

    private static native NetworkInterface getByInetAddress0(InetAddress addr)
        throws SocketException;

    Returns whether a network interface is up and running.
Throws: SocketException – if an I/O error occurs.
Returns:  true if the interface is up and running.
Since: 1.6/**
     * Returns whether a network interface is up and running.
     *
     * @return  {@code true} if the interface is up and running.
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */

    public boolean isUp() throws SocketException {
        return isUp0(name, index);
    }

    Returns whether a network interface is a loopback interface.
Throws: SocketException – if an I/O error occurs.
Returns:  true if the interface is a loopback interface.
Since: 1.6/**
     * Returns whether a network interface is a loopback interface.
     *
     * @return  {@code true} if the interface is a loopback interface.
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */

    public boolean isLoopback() throws SocketException {
        return isLoopback0(name, index);
    }

    Returns whether a network interface is a point to point interface.
A typical point to point interface would be a PPP connection through
a modem.
Throws: SocketException – if an I/O error occurs.
Returns:  true if the interface is a point to point interface.
Since: 1.6/**
     * Returns whether a network interface is a point to point interface.
     * A typical point to point interface would be a PPP connection through
     * a modem.
     *
     * @return  {@code true} if the interface is a point to point
     *          interface.
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */

    public boolean isPointToPoint() throws SocketException {
        return isP2P0(name, index);
    }

    Returns whether a network interface supports multicasting or not.
Throws: SocketException – if an I/O error occurs.
Returns:  true if the interface supports Multicasting.
Since: 1.6/**
     * Returns whether a network interface supports multicasting or not.
     *
     * @return  {@code true} if the interface supports Multicasting.
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */

    public boolean supportsMulticast() throws SocketException {
        return supportsMulticast0(name, index);
    }

    Returns the hardware address (usually MAC) of the interface if it has one and if it can be accessed given the current privileges. If a security manager is set, then the caller must have the permission NetPermission("getNetworkInformation"). 
Throws: SocketException – if an I/O error occurs.
Returns:  a byte array containing the address, or null if the address doesn't exist, is not accessible or a security manager is set and the caller does not have the permission NetPermission("getNetworkInformation")
Since: 1.6/**
     * Returns the hardware address (usually MAC) of the interface if it
     * has one and if it can be accessed given the current privileges.
     * If a security manager is set, then the caller must have
     * the permission {@link NetPermission}("getNetworkInformation").
     *
     * @return  a byte array containing the address, or {@code null} if
     *          the address doesn't exist, is not accessible or a security
     *          manager is set and the caller does not have the permission
     *          NetPermission("getNetworkInformation")
     *
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */
    public byte[] getHardwareAddress() throws SocketException {
        SecurityManager sec = System.getSecurityManager();
        if (sec != null) {
            try {
                sec.checkPermission(new NetPermission("getNetworkInformation"));
            } catch (SecurityException e) {
                if (!getInetAddresses().hasMoreElements()) {
                    // don't have connect permission to any local address
                    return null;
                }
            }
        }
        for (InetAddress addr : addrs) {
            if (addr instanceof Inet4Address) {
                return getMacAddr0(((Inet4Address)addr).getAddress(), name, index);
            }
        }
        return getMacAddr0(null, name, index);
    }

    Returns the Maximum Transmission Unit (MTU) of this interface.
Throws: SocketException – if an I/O error occurs.
Returns: the value of the MTU for that interface.
Since: 1.6/**
     * Returns the Maximum Transmission Unit (MTU) of this interface.
     *
     * @return the value of the MTU for that interface.
     * @exception       SocketException if an I/O error occurs.
     * @since 1.6
     */
    public int getMTU() throws SocketException {
        return getMTU0(name, index);
    }

    Returns whether this interface is a virtual interface (also called
subinterface).
Virtual interfaces are, on some systems, interfaces created as a child
of a physical interface and given different settings (like address or
MTU). Usually the name of the interface will the name of the parent
followed by a colon (:) and a number identifying the child since there
can be several virtual interfaces attached to a single physical
interface.
Returns: true if this interface is a virtual interface.
Since: 1.6/**
     * Returns whether this interface is a virtual interface (also called
     * subinterface).
     * Virtual interfaces are, on some systems, interfaces created as a child
     * of a physical interface and given different settings (like address or
     * MTU). Usually the name of the interface will the name of the parent
     * followed by a colon (:) and a number identifying the child since there
     * can be several virtual interfaces attached to a single physical
     * interface.
     *
     * @return {@code true} if this interface is a virtual interface.
     * @since 1.6
     */
    public boolean isVirtual() {
        return virtual;
    }

    private static native boolean isUp0(String name, int ind) throws SocketException;
    private static native boolean isLoopback0(String name, int ind) throws SocketException;
    private static native boolean supportsMulticast0(String name, int ind) throws SocketException;
    private static native boolean isP2P0(String name, int ind) throws SocketException;
    private static native byte[] getMacAddr0(byte[] inAddr, String name, int ind) throws SocketException;
    private static native int getMTU0(String name, int ind) throws SocketException;

    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 NetworkInterface as this object.  Two instances of NetworkInterface represent the same NetworkInterface if both name and addrs are the same for both. 
Params: obj –   the object to compare against.
See Also: InetAddress.getAddress()
Returns:  true if the objects are the same; false otherwise./**
     * Compares this object against the specified object.
     * The result is {@code true} if and only if the argument is
     * not {@code null} and it represents the same NetworkInterface
     * as this object.
     * <p>
     * Two instances of {@code NetworkInterface} represent the same
     * NetworkInterface if both name and addrs are the same for both.
     *
     * @param   obj   the object to compare against.
     * @return  {@code true} if the objects are the same;
     *          {@code false} otherwise.
     * @see     java.net.InetAddress#getAddress()
     */
    public boolean equals(Object obj) {
        if (!(obj instanceof NetworkInterface)) {
            return false;
        }
        NetworkInterface that = (NetworkInterface)obj;
        if (this.name != null ) {
            if (!this.name.equals(that.name)) {
                return false;
            }
        } else {
            if (that.name != null) {
                return false;
            }
        }

        if (this.addrs == null) {
            return that.addrs == null;
        } else if (that.addrs == null) {
            return false;
        }

        /* Both addrs not null. Compare number of addresses */

        if (this.addrs.length != that.addrs.length) {
            return false;
        }

        InetAddress[] thatAddrs = that.addrs;
        int count = thatAddrs.length;

        for (int i=0; i<count; i++) {
            boolean found = false;
            for (int j=0; j<count; j++) {
                if (addrs[i].equals(thatAddrs[j])) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                return false;
            }
        }
        return true;
    }

    public int hashCode() {
        return name == null? 0: name.hashCode();
    }

    public String toString() {
        String result = "name:";
        result += name == null? "null": name;
        if (displayName != null) {
            result += " (" + displayName + ")";
        }
        return result;
    }

    private static native void init();

    Returns the default network interface of this system
Returns: the default interface/**
     * Returns the default network interface of this system
     *
     * @return the default interface
     */
    static NetworkInterface getDefault() {
        return defaultInterface;
    }
}
See Also:	inetAddresses()
Returns:	an Enumeration object with all or a subset of the InetAddresses bound to this network interface
Returns:	a Stream object with all or a subset of the InetAddresses bound to this network interface
Since:	9
Returns:	a `List` object with all or a subset of the InterfaceAddresss of this network interface
Since:	1.6
See Also:	subInterfaces()
Returns:	an Enumeration object with all of the subinterfaces of this network interface
Since:	1.6
Returns:	a Stream object with all of the subinterfaces of this network interface
Since:	9
Returns:	The `NetworkInterface` this interface is attached to.
Since:	1.6
See Also:	getByIndex(int)
Returns:	the index of this network interface or `-1` if the index is unknown
Since:	1.7
Params:	name – The name of the network interface.
Throws:	SocketException – If an I/O error occurs. NullPointerException – If the specified name is `null`.
Returns:	A `NetworkInterface` with the specified name, or `null` if there is no network interface with the specified name.
Params:	index – an integer, the index of the interface
Throws:	SocketException – if an I/O error occurs. IllegalArgumentException – if index has a negative value
See Also:	getIndex()
Returns:	the NetworkInterface obtained from its index, or `null` if there is no interface with such an index on the system
Since:	1.7
Params:	addr – The `InetAddress` to search with.
Throws:	SocketException – If an I/O error occurs. NullPointerException – If the specified address is `null`.
Returns:	A `NetworkInterface` or `null` if there is no network interface with the specified IP address.
Throws:	SocketException – if an I/O error occurs, or if the platform does not have at least one configured network interface.
API Note:	this method can be used in combination with `inetAddresses()`} to obtain a stream of all IP addresses for this node, for example: `Stream<InetAddress> addrs = NetworkInterface.networkInterfaces() .flatMap(NetworkInterface::inetAddresses);`
Returns:	a Stream of NetworkInterfaces found on this machine
Since:	9
Returns:	`true` if this interface is a virtual interface.
Since:	1.6
Params:	obj – the object to compare against.
See Also:	InetAddress.getAddress()
Returns:	`true` if the objects are the same; `false` otherwise.
/

java/ 11/ java.base/java/net/NetworkInterface.java
