&gt; Complexity or learning the language is still the biggest issue I see. That has not changed in 5 years.<p>That&#x27;s not true. Most things are them same or easier than on Java8.<p>If you don&#x27;t lear Lambda&#x27;s on Java8 you are missing everything. And most things in Scala&#x27;s are like Lambda map&#x2F;foreach all over the place. and generators making things easier to read and easier to understand. Java8 doesn&#x27;t have this future you end up writing flatmap(data -&gt; return flatmap .. return flatmap return flatmpap) that&#x27;s awkward.<p>On scala if you don&#x27;t use the hard things the language is way easier than the most languages outside of the jvm ecosystem.