use SXSSF for xlsx files to avoid OurOfMemoryError issues.

project.clj

@@ -1,10 +1,10 @@
-(defproject tsv2xls "0.0.1-SNAPSHOT"
+(defproject tsv2xls "0.0.2-SNAPSHOT"
   :description "create xls(or xlsx) file from tsv file."
   :dependencies [[org.clojure/clojure		"1.3.0"]
                  [org.clojure/tools.cli		"0.2.1"]
                  [org.clojure/data.csv		"0.1.0"]
-                 [org.apache.poi/poi		"3.7"]
-                 [org.apache.poi/poi-ooxml	"3.7"]]
+                 [org.apache.poi/poi		"3.8-beta5"]
+                 [org.apache.poi/poi-ooxml	"3.8-beta5"]]
   :dev-dependencies [[swank-clojure		"1.3.3"]]
   :jvm-opts ["-Dfile.encoding=utf-8"]
   :main tsv2xls.core)

src/tsv2xls/core.clj

@@ -4,7 +4,7 @@
             [clojure.data.csv :as csv]
             [clojure.java.io :as io])
   (:import [org.apache.poi.hssf.usermodel HSSFWorkbook]
-           [org.apache.poi.xssf.usermodel XSSFWorkbook])
+           [org.apache.poi.xssf.streaming SXSSFWorkbook])
   (:gen-class))
 
 (defn tsv-to-xls-convert
@@ -14,7 +14,7 @@
               out-stream (io/output-stream outfile)]
     (let [records (csv/read-csv in-file :separator \tab :quote \|)
           book (cond (= mode "xls") (HSSFWorkbook.)
-                     (= mode "xlsx") (XSSFWorkbook.))
+                     (= mode "xlsx") (SXSSFWorkbook. 100))
           sheet (.createSheet book)]
       (.setSheetName book 0 name)
       (doseq [[i row] (map vector (iterate inc 0) records)]