How to compare the difference in minutes between 2 dates in Java 8 while also taking into account the time zone difference?

I have to compare 2 dates in Java 8 to get the difference of minutes. Now I am using java.utils.Date to store my dates but I am unable to find out how to get the difference in minutes. Also, the dates to be compared might be in 2 different time zones which should be taken into account if present. How do I proceed with this?

Example dates to be compared :

Mon Oct 12 12:20:00 IST 2020
Mon Oct 05 09:56:57 GMT 2020

The time zone difference itself does not pose any problem. Java handles that nicely. You have a problem in IST being ambiguous, though, it may stand for Irish Summer Time, Israel Standard Time, India Standard Time or something else.

java.time

I recommend you use java.time, the modern Java date and time API, for your date and time work.

	DateTimeFormatter formatter = DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz uuuu", Locale.ENGLISH);
	
	String aDateTimeString = "Mon Oct 12 12:20:00 IST 2020";
	String anotherDateTimeString = "Mon Oct 05 09:56:57 GMT 2020";
	
	ZonedDateTime aDateTime = ZonedDateTime.parse(aDateTimeString, formatter);
	ZonedDateTime anotherDateTime = ZonedDateTime.parse(anotherDateTimeString, formatter);
	long differenceInMinutes = ChronoUnit.MINUTES.between(anotherDateTime, aDateTime);
	
	System.out.format("The times are %s and %s%n", aDateTime, anotherDateTime);
	System.out.format("Difference is %d minutes%n", differenceInMinutes);

Output is:

> The times are 2020-10-12T12:20Z[Atlantic/Reykjavik] and 2020-10-05T09:56:57Z[GMT]
> Difference is 10223 minutes

Java has interpreted IST as Icelandic time. You might not have intended that. But the calculation of difference across time zones works.

I provide a link below to how to control how Java interprets IST.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• An answer of mine demonstrating how to control the interpretation of IST time zone abbreviation