Why Your Year‑Week Logic Breaks at Year‑End and How ISO‑8601 Fixes It

A real‑world bug caused by incorrect year‑week calculation is explained, then the ISO‑8601 week‑based year definition and Java's LocalDate/WeekFields APIs are introduced to reliably compute the correct year and week for any date.

Backenddatetime-apiiso-8601

0 likes · 6 min read

Why Your Year‑Week Logic Breaks at Year‑End and How ISO‑8601 Fixes It

Full-Stack Internet Architecture

Feb 3, 2020 · Fundamentals

Understanding SimpleDateFormat, Week Year, and ISO 8601 in Java

This article explains how to use Java's SimpleDateFormat for date‑time formatting and parsing, describes the pattern letters, clarifies the difference between "yyyy" and "YYYY" for week‑year calculations, and shows how ISO 8601 week definitions are supported in Java with practical code examples.

Date FormattingSimpleDateFormatiso-8601

0 likes · 8 min read

Understanding SimpleDateFormat, Week Year, and ISO 8601 in Java

Why Your Year‑Week Logic Breaks at Year‑End and How ISO‑8601 Fixes It

Understanding SimpleDateFormat, Week Year, and ISO 8601 in Java

Understanding SimpleDateFormat, Week Year, and ISO 8601 in Java