java Calendar

public static Calendar par(String dateStr,String frmat){
SimpleDateFormat sdf = new SimpleDateFormat(frmat);
Calendar cal = Calendar.getInstance();
try {
Date date = sdf.parse(dateStr);
cal.setTimeInMillis(date.getTime());
} catch (Exception e) {
return null;
}
return cal;
}
Calendar now_calendar = Calendar.getInstance();
System.out.println(now_calendar.getTime());

String y= "2011-10-21 13:10:00";
Calendar calendar = Calendar.getInstance();
calendar = par(y,"yyyy-MM-dd HH:mm:ss");
System.out.println(calendar.getTime());

Calendar calendar_before = Calendar.getInstance();
calendar_before = par(y,"yyyy-MM-dd HH:mm:ss");
calendar_before.add(calendar_before.MINUTE, -5);
System.out.println(calendar_before.getTime());
System.out.println(now_calendar.compareTo(calendar_before));

Calendar calendar_after = Calendar.getInstance();
calendar_after = par(y,"yyyy-MM-dd HH:mm:ss");
calendar_after.add(calendar_after.MINUTE, 5);
System.out.println(calendar_after.getTime());
System.out.println(now_calendar.compareTo(calendar_after));

if((now_calendar.compareTo(calendar_before)) >=0 && (now_calendar.compareTo(calendar_after)) <= 0){
System.out.println("OK");
}else{
System.out.println("NO");
}