The Java phenomenon means that programmers that once laughed at garbage
collection and strong typing have started to use it daily, and this opens up a
wonderful opportunity for the functional programming community.
Bob Harper coined the acronym HOT to summarise much of what functional
programmers have to offer the world: expertise in languages that are Higher-Order
and Typed. Bob argued for a broad interpretation of these terms, so that Higher-Order includes languages where objects contain methods (even though functions are
not first-class citizens), and Typed includes both static and dynamic typing. By
these criteria Java is HOT, and so are Haskell, ML and Scheme.