2022
Parallel Functional Programming with Java LiveLessons
    https://tutsnode.net/parallel-functional-programming-with-java/
    ! 3.7g good, including parallell streams

https://www.linkedin.com/learning/java-lambdas-and-streams
    @FunctionalInterface
    stream can only be used once

https://courses.telusko.com/learn/Java-8-stream-API-Features-Lambda-Expression