New Date() object gives the same value

Question

I have some code that utilizes the Date object as the name of a file in order to have distinct file names every time but the strange thing is that a new Date object gives off the same toString() for each loop iteration. I mean, the following:

SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
String fileName = sdf.format((d = new Date())) + ".jpg";

Log.d("Date", d.toString());

is executed in loops.

Side note: Since this is related to Java API, I haven't tagged the question as that of Android but the OS that executes this code is Android.

AFAIK, new Date() uses System.currentTimeMilis() as the init value, what might be reason for this unusual behavior?

Answer 1

You format your time as yyyyMMdd_HHmmss, but the run of a loop needs just milliseconds, so use yyyyMMdd_HHmmssSSS to get a more acurate time.

As Jon Skeet mentions in his comment, the run of a loop could even take less than a millisecond (depending on the tasks you perform), so you could run into issues with this solution as well!