The article explains that in Java's SimpleDateFormat the lowercase y pattern (year‑of‑era) should be used for calendar dates, because the uppercase Y pattern represents a week‑based year which can incorrectly roll over to the next year near year‑end, causing bugs.
This article explains how using the uppercase YYYY pattern in Java's SimpleDateFormat can incorrectly shift dates to the next year for week‑based years, demonstrates the issue with sample code, and provides guidance to avoid this subtle bug in date handling.
The article explains how using the week‑based year pattern (YYYY) instead of the calendar year pattern (yyyy) in Java's SimpleDateFormat can cause dates like 2019‑12‑31 to be displayed as 2020‑12‑31, illustrating the issue with code examples and a clear explanation of the underlying rules.
This article explains how using uppercase YYYY and DD in Java date patterns produces week‑based year and day‑of‑year values, leading to unexpected results around year boundaries, and provides code examples and best‑practice recommendations to avoid these formatting bugs.
