From the Jason website:
Note: The API will be subject to change during 2014. On January 1st 2015 it will be frozen. Do not use in production until then.
A great post on API design: https://signalvnoise.com/posts/3018-api-design-for-humans
It would be nice to know at a glance if a library has introduced incompatible API changes.
We’re still using Java 6 for our apps at work. Recently I needed to compute the number of days between 2 dates. It turns out that it’s a non–trivial problem. We’re using JBoss Seam as our web development framework, so I ended up using the Joda-Time packaged with Seam to do the computation. It’s a lovely API and much cleaner than the standard Java API.