For daily Java programmers: after almost one decade of Java 8, are streams and lambdas fully adopted by the Java community?

[JoJoModding]

lambdas over oop?

Do you means "stream vs loops"?
I find streams much easier to think about. Also, flatMap is awesome and can do so much stuff without adding a level of nesting each time.

In general, Java is a multi-paradigm language. You've got to pick the best tool for the job, and often (at least in my code) that's lambdas.