The streams api is a little verbose but this is mainly because of Java’s backwards compatibility policy. They want older code to still compile and run on new JDKs.

Default methods on interfaces help to add features to existing collections but they are limited in what they can do, hence streams.

If you really want more ergonomic collections while staying close to Java then use Kotlin which can be easily added to most Java code bases and has all the modern functional methods like map/reduce/filter/group on standard collections.

It's also to separate the methods doing computation lazily (Stream) from the one doing computation eagerly (Collection). Otherwise a simple call like isEmpty() can trigger the whole computation like in Haskell.

As a user of the API, you have to wrap your code into a Stream to be lazy evaluated, the Stream being a computation monad, so you always know if a code is evaluated eagerly or lazily.

> modern functional methods like map/reduce/filter/group

"Modern". Lol.

I know these functional concepts are far from new.

I use "modern" in this context because other contemporary languages like Python/Ruby/Scala/Rust etc all have versions of those and FP-style collection usage using these names has become popular in the last 10 years.

Java is changing: https://www.youtube.com/watch?v=gIrKP76iuPs "Venkat Subramaniam — Design Patterns in the Light of Lambda Expressions"

And you can use Scala or Clojure with Java APIs/Libraries/Frameworks

https://www.scala-lang.org/ https://typelevel.org/cats/ http://dotty.epfl.ch/

https://clojure.org/ https://clojure.org/guides/spec https://github.com/clojure/spec-alpha2/wiki/Schema-and-selec...