java获取原子钟时间并改变本地时间

 package dtm.tools;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* SyncTime 获取原子钟的时间，并设置为系统时间
* @author Administrator
*/
public class SyncTime {
private static int sleepMinutes = 0;
private static final long EPOCH_OFFSET_MILLIS;
private static final String[] hostName = {"time-a.nist.gov", "time-nw.nist.gov", "time.nist.gov"};
static {
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
// Java使用的参照标准是1970年，而时间服务器返回的秒是相当1900年的，算一下偏移
calendar.set(1900, Calendar.JANUARY, 1, 0, 0, 0);
EPOCH_OFFSET_MILLIS = Math.abs(calendar.getTime().getTime());
}
public static void main(String[] args) {
GetWebTime();
}
private static Date getNetDate(String hostName) {
Date date = null;
long result = 0;
try {
Socket socket = new Socket(hostName, 37);
BufferedInputStream bis = new BufferedInputStream(socket.getInputStream(),
socket.getReceiveBufferSize());
int b1 = bis.read();
int b2 = bis.read();
int b3 = bis.read();
int b4 = bis.read();
if ((b1 | b2 | b3 | b3) < 0) {
return null;
}
result = (((long) b1) << 24) + (b2 << 16) + (b3 << 8) + b4;
date = new Date(result * 1000 - EPOCH_OFFSET_MILLIS);
socket.close();
} catch (UnknownHostException ex) {
Logger.getLogger(SyncTime.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {