I store a number of rows in DB with the timestamp of that moment in milliseconds.
Now if I need to retrieve all rows of a given day, like today, how do I correctly create the starting and ending milliseconds of that day?

I know about SimpleDateFormat and Calendar.getInstance() briefly, but would I need to do string manipulation (which I want to avoid) to get todays date only, add the hours part and then convert it back into milliseconds, or is there a better way to do it?