mh.clj

(import (java.lang.invoke MethodHandles
                          MethodHandles$Lookup
                          MethodType
                          MethodHandle))

(def ^MethodHandle abs-handle (.findStatic (MethodHandles/lookup) 
                                           Math 
                                           "abs" 
                                           (MethodType/methodType Long/TYPE Long/TYPE)))

(.invokeWithArguments abs-handle (object-array [-42]))
;;=> 42

other.md

JRuby

[-1, 2, -3, 4].map(&java.lang.Math.method(:abs))

Kotlin

fun main(args : Array<String>) {
    val numbers = listOf<Long>(-1, 2, 3)

    println(numbers.map({ java.lang.Math.abs(it) }))
}