I have a digital copy of Programming Clojure with me, so I can give direct evidence for that now. On page 30:
Because the Java invocation syntax in Clojure is clean
and simple, it is idiomatic to use Java directly,
rather than to hide Java behind Lispy wrappers.
I believe Pragmatic Clojure says something to that effect, too, but I'll have to look it up in my dead-tree version later.
Newcomers to Clojure may dislike the intrusion of Java class and method names into their Clojure code, and rush to wrap every Java method call in a Clojure function. More experienced Clojure programmers appreciate the power offered by Java libraries and are comfortable mixing Java methods and Clojure functions.
