Set time to 00:00:00

Using java.time for more elegance

Here is how to accomplish this with java.time, Java's modern date and time API, as this is much simpler and robust:

LocalDate date = LocalDate.now(); // Today's date
LocalDateTime midnight = date.atStartOfDay(); // This is the midnight express!
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Or, if you only need time without the date:

LocalTime midnight = LocalTime.MIN; // 00:00 or Cinderella's worst nightmare😉
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Formatting date with awareness of time zone

If formatting, use SimpleDateFormat with the correct settings to avoid any midnight confusion:

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss"); // God save the Queen... of time formatting!
sdf.setTimeZone(TimeZone.getDefault()); // Not all heroes wear timezone capes
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👉 24-hour display (use "HH") can save you from a 12 hours of AM/PM lethargy.

Time Traps and Trials

Time zone trials

Time Zones can bring chaos - To avoid this, keep the time zone factor in mind while setting time:

ZonedDateTime zdt = midnight.atZone(ZoneId.systemDefault()); // Imagine zone-hopping without a passport!
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Interacting anger-free with databases

Remember, when dealing with databases, your time resetting and formatting should be compatible with your database's expectations.

The 12-hour format nemesis

Be mindful that Calendar's 12-hour format can turn your 00:00:00 into 12:00:00 AM. Use a 24-hour display setting instead:

calendar.set(Calendar.AM_PM, Calendar.AM); // AM to the rescue!
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Testing tribulations across time zones

Testing can save your day… and night. Test thoroughly across different time zones to ensure accuracy and user satisfaction.

Balancing Time: The Strikes and Gutters

LocalDateTime truncation saves the day (or night)

For a more precise hour resetting without lingering minutes and seconds, use truncatedTo(ChronoUnit.HOURS) with LocalDateTime:

LocalDateTime now = LocalDateTime.now().truncatedTo(ChronoUnit.HOURS); // Milliseconds begged to stay, but we said no!
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GregorianCalendar: The time machine

Handling older codebases? GregorianCalendar is your trusty tool:

GregorianCalendar gc = new GregorianCalendar();
gc.set(Calendar.HOUR_OF_DAY, 0); // Hours, behold the donut of destiny!
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Time setting consistency is king

Consistent time resetting is vital for a smooth run of your application, especially when it involves database interactions.