I've been working professionally in Java for almost 20 years. I can't remember the last time I saw someone use features introduced after 1.6. The time API in 1.8 was nice. I've never seen anyone use lambdas in production code. I'm sure people do use newer stuff, but I think it's the minority. So in practice it's even more stable than it is in the headlines.
I work for a large company and the code base is full of streams and lambdas. Streams are almost used too much and could be replaced with a simple for-loop.
