diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/FileSpec.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/FileSpec.kt
index b8fb1304..0956eb03 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/FileSpec.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/FileSpec.kt
@@ -4,7 +4,6 @@ import com.beust.kobalt.misc.log
 import java.io.File
 import java.nio.file.*
 import java.nio.file.attribute.BasicFileAttributes
-import java.util.*
 
 /**
  * Subclasses of IFileSpec can be turned into a list of files. There are two kings: FileSpec (a single file)
@@ -19,7 +18,7 @@ sealed class IFileSpec {
         override public fun toString() = spec
     }
 
-    class GlobSpec(val spec: ArrayList<String>) : IFileSpec() {
+    class GlobSpec(val spec: List<String>) : IFileSpec() {
 
         constructor(spec: String) : this(arrayListOf(spec))
 
diff --git a/src/test/kotlin/com/beust/kobalt/IncludeExcludeTest.kt b/src/test/kotlin/com/beust/kobalt/IncludeExcludeTest.kt
index 63fbff1a..94ca63f0 100644
--- a/src/test/kotlin/com/beust/kobalt/IncludeExcludeTest.kt
+++ b/src/test/kotlin/com/beust/kobalt/IncludeExcludeTest.kt
@@ -6,7 +6,6 @@ import org.testng.annotations.DataProvider
 import org.testng.annotations.Test
 import java.io.File
 import java.nio.file.Files
-import java.util.*
 
 class IncludeExcludeTest : KobaltTest() {
     private lateinit var topDirectory: File
@@ -31,21 +30,20 @@ class IncludeExcludeTest : KobaltTest() {
 
     @DataProvider
     fun dp() : Array<Array<out Any?>> = arrayOf(
-            arrayOf(directory, arrayListOf("A**class", "B**class"), arrayListOf<String>(), listOf(A1, B1, B2)),
-            arrayOf(directory, arrayListOf("A**class", "B**class"), arrayListOf("B*class"), listOf(A1)),
-            arrayOf(directory, arrayListOf("*class"), arrayListOf("B*class"), listOf(A1, C1, C2, C3)),
-            arrayOf(topDirectory, arrayListOf("**/*class"), arrayListOf<String>(), listOf(A1, B1, B2, C1, C2, C3)),
-            arrayOf(topDirectory, arrayListOf("*class"), arrayListOf<String>(), listOf<String>()),
-            arrayOf(topDirectory, arrayListOf("**/B*class"), arrayListOf<String>(), listOf(B1, B2)),
-            arrayOf(topDirectory, arrayListOf("**/A*class", "**/B*class"), arrayListOf("B*class"),
+            arrayOf(directory, listOf("A**class", "B**class"), listOf<String>(), listOf(A1, B1, B2)),
+            arrayOf(directory, listOf("A**class", "B**class"), listOf("B*class"), listOf(A1)),
+            arrayOf(directory, listOf("*class"), listOf("B*class"), listOf(A1, C1, C2, C3)),
+            arrayOf(topDirectory, listOf("**/*class"), listOf<String>(), listOf(A1, B1, B2, C1, C2, C3)),
+            arrayOf(topDirectory, listOf("*class"), listOf<String>(), listOf<String>()),
+            arrayOf(topDirectory, listOf("**/B*class"), listOf<String>(), listOf(B1, B2)),
+            arrayOf(topDirectory, listOf("**/A*class", "**/B*class"), listOf("B*class"),
                     listOf(A1, B1, B2)),
-            arrayOf(topDirectory, arrayListOf("**/A*class", "**/B*class"), arrayListOf("**/B*class"),
+            arrayOf(topDirectory, listOf("**/A*class", "**/B*class"), listOf("**/B*class"),
                 listOf(A1))
     )
 
     @Test(dataProvider = "dp")
-    fun shouldInclude(root: File, includedSpec: ArrayList<String>, excludedSpec: ArrayList<String>,
-            expectedFiles: List<String>) {
+    fun shouldInclude(root: File, includedSpec: List<String>, excludedSpec: List<String>, expectedFiles: List<String>) {
         val g = IFileSpec.GlobSpec(includedSpec)
         val files = g.toFiles(root.path, excludedSpec.map { Glob(it) })
         Assert.assertEquals(files.map { it.name }, expectedFiles)