Time.getJulianDay() deprecated. Which code would get the work done instead?

Question

Since Time class is deprecated, I can no longer use the getJulianDay() in the following function. I want to use Calender or GregorianCalender class to achieve the same. I partly got my answer from [question]:Time getJulianDay() deprecated which alternatives to convert date to julian and vice versa? but I'm new to such classes so I don't know how to transform the GregorianCalender to long so that I can return it in the function. How can I get the Julian Date? Thanks!

public static long normalizeDate(long startDate) {
    // normalize the start date to the beginning of the (UTC) day
    Time time = new Time();
    time.set(startDate);
    int julianDay = Time.getJulianDay(startDate, time.gmtoff);
    return time.setJulianDay(julianDay);
}

Answer 1

Does this suits what you need?

public static long normalizeDate(long startDate) {
    // normalize the start date to the beginning of the (UTC) day
    GregorianCalendar date = (GregorianCalendar)     GregorianCalendar.getInstance(TimeZone.getTimeZone("UTC"));
    date.setTime(new Date(startDate));
    date.set(Calendar.HOUR_OF_DAY, 0);
    date.set(Calendar.MINUTE, 0);
    date.set(Calendar.SECOND, 0);
    date.set(Calendar.MILLISECOND, 0);

    //transform your calendar to a long in the way you prefer
    return date.getTimeInMillis();
}