Compare dates ignoring milliseconds?

Question

Is there a way to compare two calendar objects, but ignore milliseconds?

I have written a test case that compared two calendar objects, but there is a p

Answer 1

The solution of setting the milliseconds to 0 has an issue: if the dates are 12:14:29.999 and 12:14:30.003, you will set the dates to 12:14:29 and 12:14:30 respectively and will detect a difference where you don't want to.

I have thought about a Comparator:

private static class SecondsComparator implements Comparator
{
    public int compare(Calendar o1, Calendar o2)
    {
        final long difference = o1.getTimeInMillis() - o2.getTimeInMillis();
        if (difference > -1000 && difference < 1000)
            return 0;
        else
            return difference < 0 ? 1 : -1;
    }
}

public static void main(String args[])
{
    Calendar c1 = Calendar.getInstance();
    Utils.waitMilliseconds(100);
    Calendar c2 = Calendar.getInstance();
    // will return 0 
    System.out.println(new SecondsComparator().compare(c1,c2));
}

However, it no a good solution neither, as this Comparator breaks the following rule:

The implementer must ensure that x.compareTo(y)==0 implies that sgn(x.compareTo(z)) == sgn(y.compareTo(z)), for all z.

What leads to (x=y and y=z) => x=z.

So I don't see any solution... But indeed, if you define some different dates, they are different, aren't they?