MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

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 MainClass {

    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);
    }
}