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	/*
	* Copyright (c) 1995, 2021, 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).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.net;

	import java.io.IOException;
	import java.io.UncheckedIOException;
	import java.nio.channels.DatagramChannel;
	import java.nio.channels.MulticastChannel;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.Set;
	import sun.net.NetProperties;
	import sun.nio.ch.DefaultSelectorProvider;

	/**
	* This class represents a socket for sending and receiving datagram packets.
	*
	* <p>A datagram socket is the sending or receiving point for a packet
	* delivery service. Each packet sent or received on a datagram socket
	* is individually addressed and routed. Multiple packets sent from
	* one machine to another may be routed differently, and may arrive in
	* any order.
	*
	* <p> Where possible, a newly constructed {@code DatagramSocket} has the
	* {@link StandardSocketOptions#SO_BROADCAST SO_BROADCAST} socket option enabled so as
	* to allow the transmission of broadcast datagrams. In order to receive
	* broadcast packets a DatagramSocket should be bound to the wildcard address.
	* In some implementations, broadcast packets may also be received when
	* a DatagramSocket is bound to a more specific address.
	* <p>
	* Example:
	* <pre>{@code
	* DatagramSocket s = new DatagramSocket(null);
	* s.bind(new InetSocketAddress(8888));
	* }</pre>
	* Which is equivalent to:
	* <pre>{@code
	* DatagramSocket s = new DatagramSocket(8888);
	* }</pre>
	* Both cases will create a DatagramSocket able to receive broadcasts on
	* UDP port 8888.
	*
	* <p> The {@code DatagramSocket} class defines convenience
	* methods to set and get several socket options. This class also
	* defines the {@link #setOption(SocketOption,Object) setOption}
	* and {@link #getOption(SocketOption) getOption} methods to set
	* and query socket options.
	* A {@code DatagramSocket} supports the following socket options:
	* <blockquote>
	* <a id="SocketOptions"></a>
	* <table class="striped">
	* <caption style="display:none">Socket options</caption>
	* <thead>
	* <tr>
	* <th scope="col">Option Name</th>
	* <th scope="col">Description</th>
	* </tr>
	* </thead>
	* <tbody>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#SO_SNDBUF SO_SNDBUF} </th>
	* <td> The size of the socket send buffer in bytes </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} </th>
	* <td> The size of the socket receive buffer in bytes </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#SO_REUSEADDR SO_REUSEADDR} </th>
	* <td> Re-use address </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#SO_BROADCAST SO_BROADCAST} </th>
	* <td> Allow transmission of broadcast datagrams </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#IP_TOS IP_TOS} </th>
	* <td> The Type of Service (ToS) octet in the Internet Protocol (IP) header </td>
	* </tr>
	* </tbody>
	* </table>
	* </blockquote>
	* <p> In addition, the {@code DatagramSocket} class defines methods to {@linkplain
	* #joinGroup(SocketAddress, NetworkInterface) join} and {@linkplain
	* #leaveGroup(SocketAddress, NetworkInterface) leave} a multicast group, and
	* supports <a href="DatagramSocket.html#MulticastOptions">multicast options</a> which
	* are useful when {@linkplain #joinGroup(SocketAddress, NetworkInterface) joining},
	* {@linkplain #leaveGroup(SocketAddress, NetworkInterface) leaving}, or sending datagrams
	* to a multicast group.
	* The following multicast options are supported:
	* <blockquote>
	* <a id="MulticastOptions"></a>
	* <table class="striped">
	* <caption style="display:none">Multicast options</caption>
	* <thead>
	* <tr>
	* <th scope="col">Option Name</th>
	* <th scope="col">Description</th>
	* </tr>
	* </thead>
	* <tbody>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#IP_MULTICAST_IF IP_MULTICAST_IF} </th>
	* <td> The network interface for Internet Protocol (IP) multicast datagrams </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#IP_MULTICAST_TTL
	* IP_MULTICAST_TTL} </th>
	* <td> The <em>time-to-live</em> for Internet Protocol (IP) multicast
	* datagrams </td>
	* </tr>
	* <tr>
	* <th scope="row"> {@link java.net.StandardSocketOptions#IP_MULTICAST_LOOP
	* IP_MULTICAST_LOOP} </th>
	* <td> Loopback for Internet Protocol (IP) multicast datagrams </td>
	* </tr>
	* </tbody>
	* </table>
	* </blockquote>
	* An implementation may also support additional options.
	*
	* @apiNote <a id="Multicasting"></a><b>Multicasting with DatagramSocket</b>
	*
	* <p> {@link DatagramChannel} implements the {@link MulticastChannel} interface
	* and provides an alternative API for sending and receiving multicast datagrams.
	* The {@link MulticastChannel} API supports both {@linkplain
	* MulticastChannel#join(InetAddress, NetworkInterface) any-source} and
	* {@linkplain MulticastChannel#join(InetAddress, NetworkInterface, InetAddress)
	* source-specific} multicast. Consider using {@code DatagramChannel} for
	* multicasting.
	*
	* <p> {@code DatagramSocket} can be used directly for multicasting. However,
	* contrarily to {@link MulticastSocket}, {@code DatagramSocket} doesn't call the
	* {@link DatagramSocket#setReuseAddress(boolean)} method to enable the SO_REUSEADDR
	* socket option by default. If creating a {@code DatagramSocket} intended to
	* later join a multicast group, the caller should consider explicitly enabling
	* the SO_REUSEADDR option.
	*
	* <p> An instance of {@code DatagramSocket} can be used to send or
	* receive multicast datagram packets. It is not necessary to join a multicast
	* group in order to send multicast datagrams. Before sending out multicast
	* datagram packets however, the default outgoing interface for sending
	* multicast datagram should first be configured using
	* {@link #setOption(SocketOption, Object) setOption} and
	* {@link StandardSocketOptions#IP_MULTICAST_IF}:
	*
	* <pre>{@code
	* DatagramSocket sender = new DatagramSocket(new InetSocketAddress(0));
	* NetworkInterface outgoingIf = NetworkInterface.getByName("en0");
	* sender.setOption(StandardSocketOptions.IP_MULTICAST_IF, outgoingIf);
	*
	* // optionally configure multicast TTL; the TTL defines the scope of a
	* // multicast datagram, for example, confining it to host local (0) or
	* // link local (1) etc...
	* int ttl = ...; // a number betwen 0 and 255
	* sender.setOption(StandardSocketOptions.IP_MULTICAST_TTL, ttl);
	*
	* // send a packet to a multicast group
	* byte[] msgBytes = ...;
	* InetAddress mcastaddr = InetAddress.getByName("228.5.6.7");
	* int port = 6789;
	* InetSocketAddress dest = new InetSocketAddress(mcastaddr, port);
	* DatagramPacket hi = new DatagramPacket(msgBytes, msgBytes.length, dest);
	* sender.send(hi);
	* }</pre>
	*
	* <p> An instance of {@code DatagramSocket} can also be used to receive
	* multicast datagram packets. A {@code DatagramSocket} that is created
	* with the intent of receiving multicast datagrams should be created
	* <i>unbound</i>. Before binding the socket, {@link #setReuseAddress(boolean)
	* setReuseAddress(true)} should be configured:
	*
	* <pre>{@code
	* DatagramSocket socket = new DatagramSocket(null); // unbound
	* socket.setReuseAddress(true); // set reuse address before binding
	* socket.bind(new InetSocketAddress(6789)); // bind
	*
	* // joinGroup 228.5.6.7
	* InetAddress mcastaddr = InetAddress.getByName("228.5.6.7");
	* InetSocketAddress group = new InetSocketAddress(mcastaddr, 0);
	* NetworkInterface netIf = NetworkInterface.getByName("en0");
	* socket.joinGroup(group, netIf);
	* byte[] msgBytes = new byte[1024]; // up to 1024 bytes
	* DatagramPacket packet = new DatagramPacket(msgBytes, msgBytes.length);
	* socket.receive(packet);
	* ....
	* // eventually leave group
	* socket.leaveGroup(group, netIf);
	* }</pre>
	*
	* <p><a id="PlatformDependencies"></a><b>Platform dependencies</b>
	* <p>The multicast implementation is intended to map directly to the native
	* multicasting facility. Consequently, the following items should be considered
	* when developing an application that receives IP multicast datagrams:
	* <ol>
	* <li> Contrarily to {@link DatagramChannel}, the constructors of {@code DatagramSocket}
	* do not allow to specify the {@link ProtocolFamily} of the underlying socket.
	* Consequently, the protocol family of the underlying socket may not
	* correspond to the protocol family of the multicast groups that
	* the {@code DatagramSocket} will attempt to join.
	* <br>
	* There is no guarantee that a {@code DatagramSocket} with an underlying
	* socket created in one protocol family can join and receive multicast
	* datagrams when the address of the multicast group corresponds to
	* another protocol family. For example, it is implementation specific if a
	* {@code DatagramSocket} to an IPv6 socket can join an IPv4 multicast group
	* and receive multicast datagrams sent to the group.
	* </li>
	* <li> Before joining a multicast group, the {@code DatagramSocket} should be
	* bound to the wildcard address.
	* If the socket is bound to a specific address, rather than the wildcard address
	* then it is implementation specific if multicast datagrams are received
	* by the socket.
	* </li>
	* <li> The SO_REUSEADDR option should be enabled prior to binding the socket.
	* This is required to allow multiple members of the group to bind to the same address.
	* </li>
	* </ol>
	*
	* @author Pavani Diwanji
	* @see java.net.DatagramPacket
	* @see java.nio.channels.DatagramChannel
	* @since 1.0
	*/
	public class DatagramSocket implements java.io.Closeable {

	// An instance of DatagramSocketAdaptor, NetMulticastSocket, or null
	private final DatagramSocket delegate;

	DatagramSocket delegate() {
	if (delegate == null) {
	throw new InternalError("Should not get here");
	}
	return delegate;
	}

	/**
	* All constructors eventually call this one.
	* @param delegate The wrapped DatagramSocket implementation, or null.
	*/
	DatagramSocket(DatagramSocket delegate) {
	assert delegate == null
	\|\| delegate instanceof NetMulticastSocket
	\|\| delegate instanceof sun.nio.ch.DatagramSocketAdaptor;
	this.delegate = delegate;
	}

	/**
	* Constructs a datagram socket and binds it to any available port
	* on the local host machine. The socket will be bound to the
	* {@link InetAddress#isAnyLocalAddress wildcard} address.
	*
	* <p>If there is a security manager,
	* its {@code checkListen} method is first called
	* with 0 as its argument to ensure the operation is allowed.
	* This could result in a SecurityException.
	*
	* @throws SocketException if the socket could not be opened,
	* or the socket could not be bound.
	* @throws SecurityException if a security manager exists and its
	* {@code checkListen} method doesn't allow the operation.
	*
	* @see SecurityManager#checkListen
	*/
	public DatagramSocket() throws SocketException {
	this(new InetSocketAddress(0));
	}

	/**
	* Creates an unbound datagram socket with the specified
	* DatagramSocketImpl.
	*
	* @param impl an instance of a <B>DatagramSocketImpl</B>
	* the subclass wishes to use on the DatagramSocket.
	* @since 1.4
	*/
	protected DatagramSocket(DatagramSocketImpl impl) {
	this(new NetMulticastSocket(impl));
	}

	/**
	* Creates a datagram socket, bound to the specified local
	* socket address.
	* <p>
	* If the address is {@code null} an unbound socket will be created.
	*
	* <p>If there is a security manager,
	* its {@code checkListen} method is first called
	* with the port from the socket address
	* as its argument to ensure the operation is allowed.
	* This could result in a SecurityException.
	*
	* @param bindaddr local socket address to bind, or {@code null}
	* for an unbound socket.
	*
	* @throws SocketException if the socket could not be opened,
	* or the socket could not bind to the specified local port.
	* @throws SecurityException if a security manager exists and its
	* {@code checkListen} method doesn't allow the operation.
	* @throws IllegalArgumentException if bindaddr is a
	* SocketAddress subclass not supported by this socket.
	*
	* @see SecurityManager#checkListen
	* @since 1.4
	*/
	public DatagramSocket(SocketAddress bindaddr) throws SocketException {
	this(createDelegate(bindaddr, DatagramSocket.class));
	}

	/**
	* Constructs a datagram socket and binds it to the specified port
	* on the local host machine. The socket will be bound to the
	* {@link InetAddress#isAnyLocalAddress wildcard} address.
	*
	* <p>If there is a security manager,
	* its {@code checkListen} method is first called
	* with the {@code port} argument
	* as its argument to ensure the operation is allowed.
	* This could result in a SecurityException.
	*
	* @param port local port to use in the bind operation.
	* @throws SocketException if the socket could not be opened,
	* or the socket could not bind to the specified local port.
	* @throws SecurityException if a security manager exists and its
	* {@code checkListen} method doesn't allow the operation.
	* @throws IllegalArgumentException if port is <a href="#PortRange">
	* out of range.</a>
	*
	* @see SecurityManager#checkListen
	*/
	public DatagramSocket(int port) throws SocketException {
	this(port, null);
	}

	/**
	* Creates a datagram socket, bound to the specified local
	* address.
	* <p><a id="PortRange"></a>The local port must be between 0 and
	* 65535 inclusive. A port number of {@code zero} will let the system pick
	* up an ephemeral port in a {@code bind} operation.
	* <p>
	* If the IP address is a {@link InetAddress#isAnyLocalAddress wildcard}
	* address, or is {@code null}, the socket will be bound to the wildcard
	* address.
	*
	* <p>If there is a security manager,
	* its {@code checkListen} method is first called
	* with the {@code port} argument
	* as its argument to ensure the operation is allowed.
	* This could result in a SecurityException.
	*
	* @param port local port to use in the bind operation.
	* @param laddr local address to bind (can be {@code null})
	*
	* @throws SocketException if the socket could not be opened,
	* or the socket could not bind to the specified local port.
	* @throws SecurityException if a security manager exists and its
	* {@code checkListen} method doesn't allow the operation.
	* @throws IllegalArgumentException if port is <a href="#PortRange">
	* out of range.</a>
	*
	* @see SecurityManager#checkListen
	* @since 1.1
	*/
	public DatagramSocket(int port, InetAddress laddr) throws SocketException {
	this(new InetSocketAddress(laddr, port));
	}

	/**
	* Binds this DatagramSocket to a specific address and port.
	* <p>
	* If the address is {@code null}, then the system will pick up
	* an ephemeral port and a valid local address to bind the socket.
	*
	* @param addr The address and port to bind to.
	* @throws SocketException if any error happens during the bind, or if the
	* socket is already bound.
	* @throws SecurityException if a security manager exists and its
	* {@code checkListen} method doesn't allow the operation.
	* @throws IllegalArgumentException if addr is a SocketAddress subclass
	* not supported by this socket.
	* @since 1.4
	*/
	public void bind(SocketAddress addr) throws SocketException {
	delegate().bind(addr);
	}

	/**
	* Connects the socket to a remote address for this socket. When a
	* socket is connected to a remote address, packets may only be
	* sent to or received from that address. By default a datagram
	* socket is not connected. If the socket is already closed,
	* then this method has no effect.
	*
	* <p> If this socket is not bound then this method will first cause the
	* socket to be bound to an address that is assigned automatically,
	* as if invoking the {@link #bind bind} method with a parameter of
	* {@code null}. If the remote destination to which the socket is connected
	* does not exist, or is otherwise unreachable, and if an ICMP destination
	* unreachable packet has been received for that address, then a subsequent
	* call to send or receive may throw a PortUnreachableException. Note,
	* there is no guarantee that the exception will be thrown.
	*
	* <p> If a security manager has been installed then it is invoked to check
	* access to the remote address. Specifically, if the given {@code address}
	* is a {@link InetAddress#isMulticastAddress multicast address},
	* the security manager's {@link
	* java.lang.SecurityManager#checkMulticast(InetAddress)
	* checkMulticast} method is invoked with the given {@code address}.
	* Otherwise, the security manager's {@link
	* java.lang.SecurityManager#checkConnect(String,int) checkConnect}
	* and {@link java.lang.SecurityManager#checkAccept checkAccept} methods
	* are invoked, with the given {@code address} and {@code port}, to
	* verify that datagrams are permitted to be sent and received
	* respectively.
	*
	* <p> Care should be taken to ensure that a connected datagram socket
	* is not shared with untrusted code. When a socket is connected,
	* {@link #receive receive} and {@link #send send} <b>will not perform
	* any security checks</b> on incoming and outgoing packets, other than
	* matching the packet's and the socket's address and port. On a send
	* operation, if the packet's address is set and the packet's address
	* and the socket's address do not match, an {@code IllegalArgumentException}
	* will be thrown. A socket connected to a multicast address may only
	* be used to send packets. Datagrams in the socket's {@linkplain
	* java.net.StandardSocketOptions#SO_RCVBUF socket receive buffer}, which
	* have not been {@linkplain #receive(DatagramPacket) received} before invoking
	* this method, may be discarded.
	*
	* @param address the remote address for the socket
	*
	* @param port the remote port for the socket.
	*
	* @throws IllegalArgumentException
	* if the address is null, or the port is <a href="#PortRange">
	* out of range.</a>
	*
	* @throws SecurityException
	* if a security manager has been installed and it does
	* not permit access to the given remote address
	*
	* @throws UncheckedIOException
	* may be thrown if connect fails, for example, if the
	* destination address is non-routable
	*
	* @see #disconnect
	*
	* @since 1.2
	*/
	public void connect(InetAddress address, int port) {
	delegate().connect(address, port);
	}

	/**
	* Connects this socket to a remote socket address (IP address + port number).
	*
	* <p> If given an {@link InetSocketAddress InetSocketAddress}, this method
	* behaves as if invoking {@link #connect(InetAddress,int) connect(InetAddress,int)}
	* with the given socket addresses IP address and port number, except that the
	* {@code SocketException} that may be raised is not wrapped in an
	* {@code UncheckedIOException}. Datagrams in the socket's {@linkplain
	* java.net.StandardSocketOptions#SO_RCVBUF socket receive buffer}, which
	* have not been {@linkplain #receive(DatagramPacket) received} before invoking
	* this method, may be discarded.
	*
	* @param addr The remote address.
	*
	* @throws SocketException
	* if the connect fails
	*
	* @throws IllegalArgumentException
	* if {@code addr} is {@code null}, or {@code addr} is a SocketAddress
	* subclass not supported by this socket
	*
	* @throws SecurityException
	* if a security manager has been installed and it does
	* not permit access to the given remote address
	*
	* @since 1.4
	*/
	public void connect(SocketAddress addr) throws SocketException {
	delegate().connect(addr);
	}

	/**
	* Disconnects the socket. If the socket is closed or not connected,
	* then this method has no effect.
	*
	* @apiNote If this method throws an UncheckedIOException, the socket
	* may be left in an unspecified state. It is strongly
	* recommended that the socket be closed when disconnect
	* fails.
	*
	* @throws UncheckedIOException
	* may be thrown if disconnect fails to dissolve the
	* association and restore the socket to a consistent state.
	*
	* @see #connect
	*
	* @since 1.2
	*/
	public void disconnect() {
	delegate().disconnect();
	}

	/**
	* Returns the binding state of the socket.
	* <p>
	* If the socket was bound prior to being {@link #close closed},
	* then this method will continue to return {@code true}
	* after the socket is closed.
	*
	* @return true if the socket successfully bound to an address
	* @since 1.4
	*/
	public boolean isBound() {
	return delegate().isBound();
	}

	/**
	* Returns the connection state of the socket.
	* <p>
	* If the socket was connected prior to being {@link #close closed},
	* then this method will continue to return {@code true}
	* after the socket is closed.
	*
	* @return true if the socket successfully connected to a server
	* @since 1.4
	*/
	public boolean isConnected() {
	return delegate().isConnected();
	}

	/**
	* Returns the address to which this socket is connected. Returns
	* {@code null} if the socket is not connected.
	* <p>
	* If the socket was connected prior to being {@link #close closed},
	* then this method will continue to return the connected address
	* after the socket is closed.
	*
	* @return the address to which this socket is connected.
	* @since 1.2
	*/
	public InetAddress getInetAddress() {
	return delegate().getInetAddress();
	}

	/**
	* Returns the port number to which this socket is connected.
	* Returns {@code -1} if the socket is not connected.
	* <p>
	* If the socket was connected prior to being {@link #close closed},
	* then this method will continue to return the connected port number
	* after the socket is closed.
	*
	* @return the port number to which this socket is connected.
	* @since 1.2
	*/
	public int getPort() {
	return delegate().getPort();
	}

	/**
	* Returns the address of the endpoint this socket is connected to, or
	* {@code null} if it is unconnected.
	* <p>
	* If the socket was connected prior to being {@link #close closed},
	* then this method will continue to return the connected address
	* after the socket is closed.
	*
	* @return a {@code SocketAddress} representing the remote
	* endpoint of this socket, or {@code null} if it is
	* not connected yet.
	* @see #getInetAddress()
	* @see #getPort()
	* @see #connect(SocketAddress)
	* @since 1.4
	*/
	public SocketAddress getRemoteSocketAddress() {
	return delegate().getRemoteSocketAddress();
	}

	/**
	* Returns the address of the endpoint this socket is bound to.
	*
	* @return a {@code SocketAddress} representing the local endpoint of this
	* socket, or {@code null} if it is closed or not bound yet.
	* @see #getLocalAddress()
	* @see #getLocalPort()
	* @see #bind(SocketAddress)
	* @since 1.4
	*/
	public SocketAddress getLocalSocketAddress() {
	return delegate().getLocalSocketAddress();
	}

	/**
	* Sends a datagram packet from this socket. The
	* {@code DatagramPacket} includes information indicating the
	* data to be sent, its length, the IP address of the remote host,
	* and the port number on the remote host.
	*
	* <p>If there is a security manager, and the socket is not currently
	* connected to a remote address, this method first performs some
	* security checks. First, if {@code p.getAddress().isMulticastAddress()}
	* is true, this method calls the
	* security manager's {@code checkMulticast} method
	* with {@code p.getAddress()} as its argument.
	* If the evaluation of that expression is false,
	* this method instead calls the security manager's
	* {@code checkConnect} method with arguments
	* {@code p.getAddress().getHostAddress()} and
	* {@code p.getPort()}. Each call to a security manager method
	* could result in a SecurityException if the operation is not allowed.
	*
	* @param p the {@code DatagramPacket} to be sent.
	*
	* @throws IOException if an I/O error occurs.
	* @throws SecurityException if a security manager exists and its
	* {@code checkMulticast} or {@code checkConnect}
	* method doesn't allow the send.
	* @throws PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no
	* guarantee that the exception will be thrown.
	* @throws java.nio.channels.IllegalBlockingModeException
	* if this socket has an associated channel,
	* and the channel is in non-blocking mode.
	* @throws IllegalArgumentException if the socket is connected,
	* and connected address and packet address differ, or
	* if the socket is not connected and the packet address
	* is not set or if its port is <a href="#PortRange">out of
	* range.</a>
	*
	* @see java.net.DatagramPacket
	* @see SecurityManager#checkMulticast(InetAddress)
	* @see SecurityManager#checkConnect
	* @revised 1.4
	*/
	public void send(DatagramPacket p) throws IOException {
	delegate().send(p);
	}

	/**
	* Receives a datagram packet from this socket. When this method
	* returns, the {@code DatagramPacket}'s buffer is filled with
	* the data received. The datagram packet also contains the sender's
	* IP address, and the port number on the sender's machine.
	* <p>
	* This method blocks until a datagram is received. The
	* {@code length} field of the datagram packet object contains
	* the length of the received message. If the message is longer than
	* the packet's length, the message is truncated.
	* <p>
	* If there is a security manager, and the socket is not currently
	* connected to a remote address, a packet cannot be received if the
	* security manager's {@code checkAccept} method does not allow it.
	* Datagrams that are not permitted by the security manager are silently
	* discarded.
	*
	* @param p the {@code DatagramPacket} into which to place
	* the incoming data.
	* @throws IOException if an I/O error occurs.
	* @throws SocketTimeoutException if setSoTimeout was previously called
	* and the timeout has expired.
	* @throws PortUnreachableException may be thrown if the socket is connected
	* to a currently unreachable destination. Note, there is no guarantee that the
	* exception will be thrown.
	* @throws java.nio.channels.IllegalBlockingModeException
	* if this socket has an associated channel,
	* and the channel is in non-blocking mode.
	* @see java.net.DatagramPacket
	* @see java.net.DatagramSocket
	* @revised 1.4
	*/
	public void receive(DatagramPacket p) throws IOException {
	delegate().receive(p);
	}

	/**
	* Gets the local address to which the socket is bound.
	*
	* <p>If there is a security manager, its
	* {@code checkConnect} method is first called
	* with the host address and {@code -1}
	* as its arguments to see if the operation is allowed.
	*
	* @see SecurityManager#checkConnect
	* @return the local address to which the socket is bound,
	* {@code null} if the socket is closed, or
	* an {@code InetAddress} representing
	* {@link InetAddress#isAnyLocalAddress wildcard}
	* address if either the socket is not bound, or
	* the security manager {@code checkConnect}
	* method does not allow the operation
	* @since 1.1
	*/
	public InetAddress getLocalAddress() {
	return delegate().getLocalAddress();
	}

	/**
	* Returns the port number on the local host to which this socket
	* is bound.
	*
	* @return the port number on the local host to which this socket is bound,
	* {@code -1} if the socket is closed, or
	* {@code 0} if it is not bound yet.
	*/
	public int getLocalPort() {
	return delegate().getLocalPort();
	}

	/**
	* Enable/disable SO_TIMEOUT with the specified timeout, in
	* milliseconds. With this option set to a positive timeout value,
	* a call to receive() for this DatagramSocket
	* will block for only this amount of time. If the timeout expires,
	* a <B>java.net.SocketTimeoutException</B> is raised, though the
	* DatagramSocket is still valid. A timeout of zero is interpreted
	* as an infinite timeout.
	* The option <B>must</B> be enabled prior to entering the blocking
	* operation to have effect.
	*
	* @param timeout the specified timeout in milliseconds.
	* @throws SocketException if there is an error in the underlying protocol, such as an UDP error.
	* @throws IllegalArgumentException if {@code timeout} is negative
	* @since 1.1
	* @see #getSoTimeout()
	*/
	public void setSoTimeout(int timeout) throws SocketException {
	delegate().setSoTimeout(timeout);
	}

	/**
	* Retrieve setting for SO_TIMEOUT. 0 returns implies that the
	* option is disabled (i.e., timeout of infinity).
	*
	* @return the setting for SO_TIMEOUT
	* @throws SocketException if there is an error in the underlying protocol, such as an UDP error.
	* @since 1.1
	* @see #setSoTimeout(int)
	*/
	public int getSoTimeout() throws SocketException {
	return delegate().getSoTimeout();
	}

	/**
	* Sets the SO_SNDBUF option to the specified value for this
	* {@code DatagramSocket}. The SO_SNDBUF option is used by the
	* network implementation as a hint to size the underlying
	* network I/O buffers. The SO_SNDBUF setting may also be used
	* by the network implementation to determine the maximum size
	* of the packet that can be sent on this socket.
	* <p>
	* As SO_SNDBUF is a hint, applications that want to verify
	* what size the buffer is should call {@link #getSendBufferSize()}.
	* <p>
	* Increasing the buffer size may allow multiple outgoing packets
	* to be queued by the network implementation when the send rate
	* is high.
	* <p>
	* Note: If {@link #send(DatagramPacket)} is used to send a
	* {@code DatagramPacket} that is larger than the setting
	* of SO_SNDBUF then it is implementation specific if the
	* packet is sent or discarded.
	*
	* @apiNote
	* If {@code size > 0}, this method is equivalent to calling
	* {@link #setOption(SocketOption, Object)
	* setOption(StandardSocketOptions.SO_SNDBUF, size)}.
	*
	* @param size the size to which to set the send buffer
	* size, in bytes. This value must be greater than 0.
	*
	* @throws SocketException if there is an error
	* in the underlying protocol, such as an UDP error.
	* @throws IllegalArgumentException if the value is 0 or is
	* negative.
	* @see #getSendBufferSize()
	* @see StandardSocketOptions#SO_SNDBUF
	* @since 1.2
	*/
	public void setSendBufferSize(int size) throws SocketException {
	delegate().setSendBufferSize(size);
	}

	/**
	* Get value of the SO_SNDBUF option for this {@code DatagramSocket}, that is the
	* buffer size, in bytes, used by the platform for output on this {@code DatagramSocket}.
	*
	* @apiNote
	* This method is equivalent to calling {@link #getOption(SocketOption)
	* getOption(StandardSocketOptions.SO_SNDBUF)}.
	*
	* @return the value of the SO_SNDBUF option for this {@code DatagramSocket}
	* @throws SocketException if there is an error in
	* the underlying protocol, such as an UDP error.
	* @see #setSendBufferSize
	* @see StandardSocketOptions#SO_SNDBUF
	* @since 1.2
	*/
	public int getSendBufferSize() throws SocketException {
	return delegate().getSendBufferSize();
	}

	/**
	* Sets the SO_RCVBUF option to the specified value for this
	* {@code DatagramSocket}. The SO_RCVBUF option is used by
	* the network implementation as a hint to size the underlying
	* network I/O buffers. The SO_RCVBUF setting may also be used
	* by the network implementation to determine the maximum size
	* of the packet that can be received on this socket.
	* <p>
	* Because SO_RCVBUF is a hint, applications that want to
	* verify what size the buffers were set to should call
	* {@link #getReceiveBufferSize()}.
	* <p>
	* Increasing SO_RCVBUF may allow the network implementation
	* to buffer multiple packets when packets arrive faster than
	* are being received using {@link #receive(DatagramPacket)}.
	* <p>
	* Note: It is implementation specific if a packet larger
	* than SO_RCVBUF can be received.
	*
	* @apiNote
	* If {@code size > 0}, this method is equivalent to calling
	* {@link #setOption(SocketOption, Object)
	* setOption(StandardSocketOptions.SO_RCVBUF, size)}.
	*
	* @param size the size to which to set the receive buffer
	* size, in bytes. This value must be greater than 0.
	*
	* @throws SocketException if there is an error in
	* the underlying protocol, such as an UDP error.
	* @throws IllegalArgumentException if the value is 0 or is
	* negative.
	* @see #getReceiveBufferSize()
	* @see StandardSocketOptions#SO_RCVBUF
	* @since 1.2
	*/
	public void setReceiveBufferSize(int size) throws SocketException {
	delegate().setReceiveBufferSize(size);
	}

	/**
	* Get value of the SO_RCVBUF option for this {@code DatagramSocket}, that is the
	* buffer size, in bytes, used by the platform for input on this {@code DatagramSocket}.
	*
	* @apiNote
	* This method is equivalent to calling {@link #getOption(SocketOption)
	* getOption(StandardSocketOptions.SO_RCVBUF)}.
	*
	* @return the value of the SO_RCVBUF option for this {@code DatagramSocket}
	* @throws SocketException if there is an error in the underlying protocol, such as an UDP error.
	* @see #setReceiveBufferSize(int)
	* @see StandardSocketOptions#SO_RCVBUF
	* @since 1.2
	*/
	public int getReceiveBufferSize() throws SocketException {
	return delegate().getReceiveBufferSize();
	}

	/**
	* Enable/disable the SO_REUSEADDR socket option.
	* <p>
	* For UDP sockets it may be necessary to bind more than one
	* socket to the same socket address. This is typically for the
	* purpose of receiving multicast packets
	* (See {@link java.net.MulticastSocket}). The
	* {@code SO_REUSEADDR} socket option allows multiple
	* sockets to be bound to the same socket address if the
	* {@code SO_REUSEADDR} socket option is enabled prior
	* to binding the socket using {@link #bind(SocketAddress)}.
	* <p>
	* Note: This functionality is not supported by all existing platforms,
	* so it is implementation specific whether this option will be ignored
	* or not. However, if it is not supported then
	* {@link #getReuseAddress()} will always return {@code false}.
	* <p>
	* When a {@code DatagramSocket} is created the initial setting
	* of {@code SO_REUSEADDR} is disabled.
	* <p>
	* The behaviour when {@code SO_REUSEADDR} is enabled or
	* disabled after a socket is bound (See {@link #isBound()})
	* is not defined.
	*
	* @apiNote
	* This method is equivalent to calling {@link #setOption(SocketOption, Object)
	* setOption(StandardSocketOptions.SO_REUSEADDR, on)}.
	*
	* @param on whether to enable or disable the
	* @throws SocketException if an error occurs enabling or
	* disabling the {@code SO_REUSEADDR} socket option,
	* or the socket is closed.
	* @since 1.4
	* @see #getReuseAddress()
	* @see #bind(SocketAddress)
	* @see #isBound()
	* @see #isClosed()
	* @see StandardSocketOptions#SO_REUSEADDR
	*/
	public void setReuseAddress(boolean on) throws SocketException {
	delegate().setReuseAddress(on);
	}

	/**
	* Tests if SO_REUSEADDR is enabled.
	*
	* @apiNote
	* This method is equivalent to calling {@link #getOption(SocketOption)
	* getOption(StandardSocketOptions.SO_REUSEADDR)}.
	*
	* @return a {@code boolean} indicating whether or not SO_REUSEADDR is enabled.
	* @throws SocketException if there is an error
	* in the underlying protocol, such as an UDP error.
	* @since 1.4
	* @see #setReuseAddress(boolean)
	* @see StandardSocketOptions#SO_REUSEADDR
	*/
	public boolean getReuseAddress() throws SocketException {
	return delegate().getReuseAddress();
	}

	/**
	* Enable/disable SO_BROADCAST.
	*
	* <p> Some operating systems may require that the Java virtual machine be
	* started with implementation specific privileges to enable this option or
	* send broadcast datagrams.
	*
	* @apiNote
	* This method is equivalent to calling {@link #setOption(SocketOption, Object)
	* setOption(StandardSocketOptions.SO_BROADCAST, on)}.
	*
	* @param on
	* whether or not to have broadcast turned on.
	*
	* @throws SocketException
	* if there is an error in the underlying protocol, such as an UDP
	* error.
	*
	* @since 1.4
	* @see #getBroadcast()
	* @see StandardSocketOptions#SO_BROADCAST
	*/
	public void setBroadcast(boolean on) throws SocketException {
	delegate().setBroadcast(on);
	}

	/**
	* Tests if SO_BROADCAST is enabled.
	*
	* @apiNote
	* This method is equivalent to calling {@link #getOption(SocketOption)
	* getOption(StandardSocketOptions.SO_BROADCAST)}.
	*
	* @return a {@code boolean} indicating whether or not SO_BROADCAST is enabled.
	* @throws SocketException if there is an error
	* in the underlying protocol, such as an UDP error.
	* @since 1.4
	* @see #setBroadcast(boolean)
	* @see StandardSocketOptions#SO_BROADCAST
	*/
	public boolean getBroadcast() throws SocketException {
	return delegate().getBroadcast();
	}

	/**
	* Sets traffic class or type-of-service octet in the IP
	* datagram header for datagrams sent from this DatagramSocket.
	* As the underlying network implementation may ignore this
	* value applications should consider it a hint.
	*
	* <P> The tc <B>must</B> be in the range {@code 0 <= tc <=
	* 255} or an IllegalArgumentException will be thrown.
	* <p>Notes:
	* <p>For Internet Protocol v4 the value consists of an
	* {@code integer}, the least significant 8 bits of which
	* represent the value of the TOS octet in IP packets sent by
	* the socket.
	* RFC 1349 defines the TOS values as follows:
	*
	* <UL>
	* <LI><CODE>IPTOS_LOWCOST (0x02)</CODE></LI>
	* <LI><CODE>IPTOS_RELIABILITY (0x04)</CODE></LI>
	* <LI><CODE>IPTOS_THROUGHPUT (0x08)</CODE></LI>
	* <LI><CODE>IPTOS_LOWDELAY (0x10)</CODE></LI>
	* </UL>
	* The last low order bit is always ignored as this
	* corresponds to the MBZ (must be zero) bit.
	* <p>
	* Setting bits in the precedence field may result in a
	* SocketException indicating that the operation is not
	* permitted.
	* <p>
	* for Internet Protocol v6 {@code tc} is the value that
	* would be placed into the sin6_flowinfo field of the IP header.
	*
	* @apiNote
	* This method is equivalent to calling {@link #setOption(SocketOption, Object)
	* setOption(StandardSocketOptions.IP_TOS, tc)}.
	*
	* @param tc an {@code int} value for the bitset.
	* @throws SocketException if there is an error setting the
	* traffic class or type-of-service
	* @since 1.4
	* @see #getTrafficClass
	* @see StandardSocketOptions#IP_TOS
	*/
	public void setTrafficClass(int tc) throws SocketException {
	delegate().setTrafficClass(tc);
	}

	/**
	* Gets traffic class or type-of-service in the IP datagram
	* header for packets sent from this DatagramSocket.
	* <p>
	* As the underlying network implementation may ignore the
	* traffic class or type-of-service set using {@link #setTrafficClass(int)}
	* this method may return a different value than was previously
	* set using the {@link #setTrafficClass(int)} method on this
	* DatagramSocket.
	*
	* @apiNote
	* This method is equivalent to calling {@link #getOption(SocketOption)
	* getOption(StandardSocketOptions.IP_TOS)}.
	*
	* @return the traffic class or type-of-service already set
	* @throws SocketException if there is an error obtaining the
	* traffic class or type-of-service value.
	* @since 1.4
	* @see #setTrafficClass(int)
	* @see StandardSocketOptions#IP_TOS
	*/
	public int getTrafficClass() throws SocketException {
	return delegate().getTrafficClass();
	}

	/**
	* Closes this datagram socket.
	* <p>
	* Any thread currently blocked in {@link #receive} upon this socket
	* will throw a {@link SocketException}.
	*
	* <p> If this socket has an associated channel then the channel is closed
	* as well.
	*
	* @revised 1.4
	*/
	public void close() {
	delegate().close();
	}

	/**
	* Returns whether the socket is closed or not.
	*
	* @return true if the socket has been closed
	* @since 1.4
	*/
	public boolean isClosed() {
	return delegate().isClosed();
	}

	/**
	* Returns the unique {@link java.nio.channels.DatagramChannel} object
	* associated with this datagram socket, if any.
	*
	* <p> A datagram socket will have a channel if, and only if, the channel
	* itself was created via the {@link java.nio.channels.DatagramChannel#open
	* DatagramChannel.open} method.
	*
	* @return the datagram channel associated with this datagram socket,
	* or {@code null} if this socket was not created for a channel
	*
	* @since 1.4
	*/
	public DatagramChannel getChannel() {
	return null;
	}

	/**
	* User defined factory for all datagram sockets.
	*/
	private static volatile DatagramSocketImplFactory factory;

	/**
	* Sets the datagram socket implementation factory for the
	* application. The factory can be specified only once.
	* <p>
	* When an application creates a new datagram socket, the socket
	* implementation factory's {@code createDatagramSocketImpl} method is
	* called to create the actual datagram socket implementation.
	* <p>
	* Passing {@code null} to the method is a no-op unless the factory
	* was already set.
	*
	* <p>If there is a security manager, this method first calls
	* the security manager's {@code checkSetFactory} method
	* to ensure the operation is allowed.
	* This could result in a SecurityException.
	*
	* @param fac the desired factory.
	* @throws IOException if an I/O error occurs when setting the
	* datagram socket factory.
	* @throws SocketException if the factory is already defined.
	* @throws SecurityException if a security manager exists and its
	* {@code checkSetFactory} method doesn't allow the operation.
	* @see java.net.DatagramSocketImplFactory#createDatagramSocketImpl()
	* @see SecurityManager#checkSetFactory
	* @since 1.3
	*
	* @deprecated Use {@link DatagramChannel}, or subclass {@code DatagramSocket}
	* directly.
	* <br> This method provided a way in early JDK releases to replace the
	* system wide implementation of {@code DatagramSocket}. It has been mostly
	* obsolete since Java 1.4. If required, a {@code DatagramSocket} can be
	* created to use a custom implementation by extending {@code DatagramSocket}
	* and using the {@linkplain #DatagramSocket(DatagramSocketImpl) protected
	* constructor} that takes an {@linkplain DatagramSocketImpl implementation}
	* as a parameter.
	*/
	@Deprecated(since = "17")
	public static synchronized void
	setDatagramSocketImplFactory(DatagramSocketImplFactory fac)
	throws IOException
	{
	if (factory != null) {
	throw new SocketException("factory already defined");
	}
	@SuppressWarnings("removal")
	SecurityManager security = System.getSecurityManager();
	if (security != null) {
	security.checkSetFactory();
	}
	factory = fac;
	}

	/**
	* Sets the value of a socket option.
	*
	* @param <T> The type of the socket option value
	* @param name The socket option
	* @param value The value of the socket option. A value of {@code null}
	* may be valid for some options.
	*
	* @return this DatagramSocket
	*
	* @throws UnsupportedOperationException if the datagram socket
	* does not support the option.
	*
	* @throws IllegalArgumentException if the value is not valid for
	* the option.
	*
	* @throws IOException if an I/O error occurs, or if the socket is closed.
	*
	* @throws SecurityException if a security manager is set and if the socket
	* option requires a security permission and if the caller does
	* not have the required permission.
	* {@link java.net.StandardSocketOptions StandardSocketOptions}
	* do not require any security permission.
	*
	* @throws NullPointerException if name is {@code null}
	*
	* @since 9
	*/
	public <T> DatagramSocket setOption(SocketOption<T> name, T value)
	throws IOException
	{
	delegate().setOption(name, value);
	return this;
	}

	/**
	* Returns the value of a socket option.
	*
	* @param <T> The type of the socket option value
	* @param name The socket option
	*
	* @return The value of the socket option.
	*
	* @throws UnsupportedOperationException if the datagram socket
	* does not support the option.
	*
	* @throws IOException if an I/O error occurs, or if the socket is closed.
	*
	* @throws NullPointerException if name is {@code null}
	*
	* @throws SecurityException if a security manager is set and if the socket
	* option requires a security permission and if the caller does
	* not have the required permission.
	* {@link java.net.StandardSocketOptions StandardSocketOptions}
	* do not require any security permission.
	*
	* @since 9
	*/
	public <T> T getOption(SocketOption<T> name) throws IOException {
	return delegate().getOption(name);
	}

	/**
	* Returns a set of the socket options supported by this socket.
	*
	* This method will continue to return the set of options even after
	* the socket has been closed.
	*
	* @return A set of the socket options supported by this socket. This set
	* may be empty if the socket's DatagramSocketImpl cannot be created.
	*
	* @since 9
	*/
	public Set<SocketOption<?>> supportedOptions() {
	return delegate().supportedOptions();
	}

	/**
	* Joins a multicast group.
	*
	* <p> In order to join a multicast group, the caller should specify
	* the IP address of the multicast group to join, and the local
	* {@linkplain NetworkInterface network interface} to receive multicast
	* packets from.
	* <ul>
	* <li> The {@code mcastaddr} argument indicates the IP address
	* of the multicast group to join. For historical reasons this is
	* specified as a {@code SocketAddress}.
	* The default implementation only supports {@link InetSocketAddress} and
	* the {@link InetSocketAddress#getPort() port} information is ignored.
	* </li>
	* <li> The {@code netIf} argument specifies the local interface to receive
	* multicast datagram packets, or {@code null} to defer to the interface
	* set for outgoing multicast datagrams.
	* If {@code null}, and no interface has been set, the behaviour is
	* unspecified: any interface may be selected or the operation may fail
	* with a {@code SocketException}.
	* </li>
	* </ul>
	*
	* <p> It is possible to call this method several times to join
	* several different multicast groups, or join the same group
	* in several different networks. However, if the socket is already a
	* member of the group, an {@link IOException} will be thrown.
	*
	* <p>If there is a security manager, this method first
	* calls its {@code checkMulticast} method with the {@code mcastaddr}
	* argument as its argument.
	*
	* @apiNote The default interface for sending outgoing multicast datagrams
	* can be configured with {@link #setOption(SocketOption, Object)}
	* with {@link StandardSocketOptions#IP_MULTICAST_IF}.
	*
	* @param mcastaddr indicates the multicast address to join.
	* @param netIf specifies the local interface to receive multicast
	* datagram packets, or {@code null}.
	* @throws IOException if there is an error joining, or when the address
	* is not a multicast address, or the platform does not support
	* multicasting
	* @throws SecurityException if a security manager exists and its
	* {@code checkMulticast} method doesn't allow the join.
	* @throws IllegalArgumentException if mcastaddr is {@code null} or is a
	* SocketAddress subclass not supported by this socket
	* @see SecurityManager#checkMulticast(InetAddress)
	* @see DatagramChannel#join(InetAddress, NetworkInterface)
	* @see StandardSocketOptions#IP_MULTICAST_IF
	* @since 17
	*/
	public void joinGroup(SocketAddress mcastaddr, NetworkInterface netIf)
	throws IOException {
	delegate().joinGroup(mcastaddr, netIf);
	}

	/**
	* Leave a multicast group on a specified local interface.
	*
	* <p>If there is a security manager, this method first
	* calls its {@code checkMulticast} method with the
	* {@code mcastaddr} argument as its argument.
	*
	* @apiNote
	* The {@code mcastaddr} and {@code netIf} arguments should identify
	* a multicast group that was previously {@linkplain
	* #joinGroup(SocketAddress, NetworkInterface) joined} by
	* this {@code DatagramSocket}.
	* <p> It is possible to call this method several times to leave
	* multiple different multicast groups previously joined, or leave
	* the same group previously joined in multiple different networks.
	* However, if the socket is not a member of the specified group
	* in the specified network, an {@link IOException} will be
	* thrown.
	*
	* @param mcastaddr is the multicast address to leave. This should
	* contain the same IP address than that used for {@linkplain
	* #joinGroup(SocketAddress, NetworkInterface) joining}
	* the group.
	* @param netIf specifies the local interface or {@code null} to defer
	* to the interface set for outgoing multicast datagrams.
	* If {@code null}, and no interface has been set, the behaviour
	* is unspecified: any interface may be selected or the operation
	* may fail with a {@code SocketException}.
	* @throws IOException if there is an error leaving or when the address
	* is not a multicast address.
	* @throws SecurityException if a security manager exists and its
	* {@code checkMulticast} method doesn't allow the operation.
	* @throws IllegalArgumentException if mcastaddr is {@code null} or is a
	* SocketAddress subclass not supported by this socket.
	* @see SecurityManager#checkMulticast(InetAddress)
	* @see #joinGroup(SocketAddress, NetworkInterface)
	* @see StandardSocketOptions#IP_MULTICAST_IF
	* @since 17
	*/
	public void leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf)
	throws IOException {
	delegate().leaveGroup(mcastaddr, netIf);
	}

	// Temporary solution until JDK-8237352 is addressed
	private static final SocketAddress NO_DELEGATE = new SocketAddress() {};
	private static final boolean USE_PLAINDATAGRAMSOCKET = usePlainDatagramSocketImpl();

	private static boolean usePlainDatagramSocketImpl() {
	PrivilegedAction<String> pa = () -> NetProperties.get("jdk.net.usePlainDatagramSocketImpl");
	@SuppressWarnings("removal")
	String s = AccessController.doPrivileged(pa);
	return (s != null) && (s.isEmpty() \|\| s.equalsIgnoreCase("true"));
	}

	/**
	* Best effort to convert an {@link IOException}
	* into a {@link SocketException}.
	*
	* @param e an instance of {@link IOException}
	* @return an instance of {@link SocketException}
	*/
	private static SocketException toSocketException(IOException e) {
	if (e instanceof SocketException)
	return (SocketException) e;
	Throwable cause = e.getCause();
	if (cause instanceof SocketException)
	return (SocketException) cause;
	SocketException se = new SocketException(e.getMessage());
	se.initCause(e);
	return se;
	}

	/**
	* Creates a delegate for the specific requested {@code type}. This method should
	* only be called by {@code DatagramSocket} and {@code MulticastSocket}
	* public constructors.
	*
	* @param bindaddr An address to bind to, or {@code null} if creating an unbound
	* socket.
	* @param type This is either {@code MulticastSocket.class}, if the delegate needs
	* to support joining multicast groups, or {@code DatagramSocket.class},
	* if it doesn't. Typically, this will be {@code DatagramSocket.class}
	* when creating a delegate for {@code DatagramSocket}, and
	* {@code MulticastSocket.class} when creating a delegate for
	* {@code MulticastSocket}.
	* @param <T> The target type for which the delegate is created.
	* This is either {@code java.net.DatagramSocket} or
	* {@code java.net.MulticastSocket}.
	* @return {@code null} if {@code bindaddr == NO_DELEGATE}, otherwise returns a
	* delegate for the requested {@code type}.
	* @throws SocketException if an exception occurs while creating or binding the
	* the delegate.
	*/
	static <T extends DatagramSocket> T createDelegate(SocketAddress bindaddr, Class<T> type)
	throws SocketException {

	// Temporary solution until JDK-8237352 is addressed
	if (bindaddr == NO_DELEGATE) return null;

	assert type == DatagramSocket.class \|\| type == MulticastSocket.class;
	boolean multicast = (type == MulticastSocket.class);
	DatagramSocket delegate = null;
	boolean initialized = false;
	try {
	DatagramSocketImplFactory factory = DatagramSocket.factory;
	if (USE_PLAINDATAGRAMSOCKET \|\| factory != null) {
	// create legacy DatagramSocket delegate
	DatagramSocketImpl impl;
	if (factory != null) {
	impl = factory.createDatagramSocketImpl();
	} else {
	impl = DefaultDatagramSocketImplFactory.createDatagramSocketImpl(multicast);
	}
	delegate = new NetMulticastSocket(impl);
	((NetMulticastSocket) delegate).getImpl(); // ensure impl.create() is called.
	} else {
	// create NIO adaptor
	delegate = DefaultSelectorProvider.get()
	.openUninterruptibleDatagramChannel()
	.socket();
	}

	if (multicast) {
	// set reuseaddress if multicasting
	// (must be set before binding)
	delegate.setReuseAddress(true);
	}

	if (bindaddr != null) {
	// bind if needed
	delegate.bind(bindaddr);
	}

	// enable broadcast if possible
	try {
	delegate.setBroadcast(true);
	} catch (IOException ioe) {
	}

	initialized = true;
	} catch (IOException ioe) {
	throw toSocketException(ioe);
	} finally {
	// make sure the delegate is closed if anything
	// went wrong
	if (!initialized && delegate != null) {
	delegate.close();
	}
	}
	@SuppressWarnings("unchecked")
	T result = (T) delegate;
	return result;
	}

	}

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