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import java.io.IOException;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.DatagramChannel;
import java.util.Date;
public class Main {
public static void main(String[] args) throws IOException {
DatagramChannel channel = DatagramChannel.open();
SocketAddress address = new InetSocketAddress(0);
DatagramSocket socket = channel.socket();
socket.bind(address);
SocketAddress server = new InetSocketAddress("time-a.nist.gov", 37);
channel.connect(server);
ByteBuffer buffer = ByteBuffer.allocate(8);
buffer.order(ByteOrder.BIG_ENDIAN);
// send a byte of data to the server
buffer.put((byte) 0);
buffer.flip();
channel.write(buffer);
// get the buffer ready to receive data
buffer.clear();
// fill the first four bytes with zeros
buffer.putInt(0);
channel.read(buffer);
buffer.flip();
// convert seconds since 1900 to a java.util.Date
long secondsSince1900 = buffer.getLong();
long differenceBetweenEpochs = 2208988800L;
long secondsSince1970 = secondsSince1900 - differenceBetweenEpochs;
long msSince1970 = secondsSince1970 * 1000;
Date time = new Date(msSince1970);
System.out.println(time);
}
}
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