I haven't worked with Java much, but have done enough to have a thorough dislike of its built-in date libs. Trying to parse dates, for example, "2019-01-40" is accepted, and actually returns February 9, 2019. I'm not aware of Any other date lib that would accept this. The behavior was certainly surprising to me. Only found out because my QA guy at the time tried it, was also surprised by the result and filed a bug against one of my releases of a web service. Closed it out as won't fix.