Despite the long wait for lambda expressions in Java, the argument has been settled,
and Java is a better language for them. Whether the majority of ordinary Java pro‐
grammers require the added power—and attendant complexity—that comes from
an advanced (and much less nominal) type system such as Scala's, or whether the
“slightly functional programming” of Java 8 (e.g., map , ilter , reduce , and their peers)
will suffice for most developers' needs, remains to be seen in the months and years
ahead. It should be an interesting journey.