A user reported a very strange issue - when a document with a date field is saved, it changes the value one day to the past. With every save. But only for some dates, not all. It turned out to be a mystery that goes deep into XPages and Notes/Java APIs. I've posted a sample on OpenNTF Discord and Serdar tried it on his server - no issue. But he uses the GMT zone and I have CET (Windows set to UTC+1 - Amsterdam, Berlin... to be precise). To cut it short, the issue is caused by daylight saving interpretation between Notes and Java. The date fields (because XPages have no notion of real date-only fields) are stored with 00:00 time component and for some dates the conversion back to Java Date resulted in 23:00 on the previous day. XPages that get the date component as String for the input field, which is then saved back as a previous day during document save. The app is full of date fields and I couldn't add custom logic to every save operation, so I tried to fix it at XPages conv
While doing XPages application performance optimization, I discovered that one of the slowest parts was reading the template version and build date. I've never paid much attention to this code, so it surprised me.