Get a clojure reader using the encoding by the BOM

gistfile1.clj

(ns util
  (:require [clojure.java.io :as io])
  (:import org.apache.commons.io.input.BOMInputStream
           org.apache.commons.io.ByteOrderMark))

(defn bom-reader
  "Returns a BOM contextual reader with the proper encoding set (= BOM), defaults to UTF-8"
  [input-stream]
  (let [bom-array
        (into-array [ByteOrderMark/UTF_16LE
                     ByteOrderMark/UTF_16BE
                     ByteOrderMark/UTF_8
                     ByteOrderMark/UTF_32BE
                     ByteOrderMark/UTF_32LE])
        bom-stream (BOMInputStream. input-stream false bom-array)
        char-set-name (.getCharsetName (or (.getBOM bom-stream) ByteOrderMark/UTF_8))]
    (io/reader bom-stream :encoding char-set-name)))

Note the byte order mark is not included in the stream. Contrary to @biggert original.