import java.text.SimpleDateFormat;
import java.util.Calendar;

public class DateTimeHelper {
  public static final String DATE_FORMAT_NOW = "yyyy-MM-dd H:mm:ss:SSS";

  public static String now() {
    Calendar cal = Calendar.getInstance();
    SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
    return sdf.format(cal.getTime());
  }
}