Added measureTimeMillis blocks and comments.

src/main/kotlin/com/example/Main.kt

@@ -3,6 +3,7 @@ package com.example
 import org.apache.commons.compress.archivers.zip.*
 import java.io.File
 import java.util.*
+import kotlin.system.measureTimeMillis
 
 internal var allFilesPredicate: ZipArchiveEntryPredicate = ZipArchiveEntryPredicate { true }
 
@@ -15,20 +16,25 @@ fun main(args: Array<String>) {
     rezip3(kobalt, src, zip)
 }
 
+// Straight raw copy, not very flexible
 fun rezip(jarIn: File, zipOut: File) {
-    val s = System.currentTimeMillis()
+    val time = measureTimeMillis {
         val zos = ZipArchiveOutputStream(zipOut)
         zos.encoding = "UTF-8"
         val zip = ZipFile(jarIn)
+
         zip.copyRawEntries(zos, allFilesPredicate)
+
         zos.close()
         zip.close()
+    }
 
-    println("Rezip Time: " + (System.currentTimeMillis() - s) + "ms")
+    println("Rezip Time: $time ms")
 }
 
+// Raw copy: jar -> zip
 fun rezip2(jarIn: File, zipOut: File) {
-    val s = System.currentTimeMillis()
+    val time = measureTimeMillis {
         val zos = ZipArchiveOutputStream(zipOut)
         zos.encoding = "UTF-8"
         val zip = ZipFile(jarIn)
@@ -40,26 +46,32 @@ fun rezip2(jarIn: File, zipOut: File) {
         zos.close()
 
         zip.close()
+    }
 
-    println("Rezip2 Time: " + (System.currentTimeMillis() - s) + "ms")
+    println("Rezip2 Time: $time ms")
 }
 
+// Raw copy: jar x 2 -> zip
 fun rezip3(jarIn: File, srcJar: File, zipOut: File) {
-    val s = System.currentTimeMillis()
+    val time = measureTimeMillis {
         val zos = ZipArchiveOutputStream(zipOut)
         zos.encoding = "UTF-8"
         val jar = ZipFile(jarIn)
 
+        // get the jar entries
         val jarEntries = jar.entries
 
+        // copy the entries
         for (entry in jar.entries) {
             zos.addRawArchiveEntry(entry, jar.getRawInputStream(entry))
         }
 
         jar.close()
 
+        // get the src jar entries
         val src = ZipFile(srcJar)
 
+        // copy the entries, no dups
         for (entry in src.entries) {
             if (!entryExists(jarEntries, entry)) {
                 zos.addRawArchiveEntry(entry, src.getRawInputStream(entry))
@@ -67,12 +79,13 @@ fun rezip3(jarIn: File, srcJar: File, zipOut: File) {
         }
 
         src.close()
-
         zos.close()
+    }
 
-    println("Rezip3 Time: " + (System.currentTimeMillis() - s) + "ms")
+    println("Rezip3 Time: $time ms")
 }
 
+// Look for duplicate entries
 fun entryExists(jarEntries: Enumeration<ZipArchiveEntry>, entry: ZipArchiveEntry): Boolean {
     for (e in jarEntries) {
         if (e.name == entry.name) {