How to accurately calculate the number of days between two dates in Java?

[divorcelawyerseo1]

Hello everyone,

I’m currently working on a small Java project where I need to calculate the difference between two dates (days, months, and years). While Java’s LocalDate and ChronoUnit work fine in simple cases, I’m running into issues when dealing with:

• Different month lengths
• Leap years
• Historical date edge cases

I’ve been comparing my results with some online date calculation tools to verify accuracy. One example I found useful is an online date calculator that shows date differences, adds/subtracts days, and handles calendar logic quite cleanly:
https://calculatedatetime.com/date-calculator/

My questions are:

1. What is the best practice in Java for handling date difference calculations reliably?
2. Should I rely solely on java.time, or are there edge cases I should manually handle?
3. How do you usually validate your results when building a date or time calculator?

Any advice or sample code would be greatly appreciated. Thanks in advance!

---

If you want, I can also:

• Rewrite this for Stack Overflow, Quora, or Reddit
• Make it more beginner-focused or more advanced
• Create multiple variations for posting on different forums without duplication