Usage of java methods as a function argument in Clojure

Question

How can I use java methods as a functions arguments in Clojure?

For example, I want to make a functions composition:

user> (Integer. (str \\9))
9
user         


        

Answer 1

Unlike Clojure functions, Java methods weren't designed to be first class. When you use Java inter-op in Clojure, you're literally working with Java methods, so you don't get the added benefits that were implemented for Clojure functions. For more info, see the comments below.

As a workaround to use Java methods as arguments, you can wrap them in an anonymous function, like this, effectively making them Clojure functions:

((comp #(Integer. %) str) \9)