Having functional program in java? http://codemonkeyism.com/functional-programming/ 

Functional programming in old java, with eclipse template - http://www.javacodegeeks.com/2012/03/functional-programming-with-map-and.html

Functional Programming For The Rest of Us - http://www.defmacro.org/ramblings/fp.html?

collection-pipeline - http://martinfowler.com/articles/collection-pipeline/

Make code composable - https://hackernoon.com/practical-functional-programming-6d7932abc58b

A primer on functional architecture - https://increment.com/software-architecture/primer-on-functional-architecture/