Senior Brother's Insights

Jan 1, 2020 · Fundamentals

Why Using “YYYY” in SimpleDateFormat Breaks Dates Around New Year (and How to Fix It)

Around the 2020 New Year many Java applications displayed dates like 2020/12/31 due to a subtle bug in SimpleDateFormat when using the pattern "YYYY" instead of "yyyy", which can be reproduced, explained, and resolved with a simple pattern change.