diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/GenericRunner.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/GenericRunner.kt
index a779cd1e..5938d7b1 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/GenericRunner.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/GenericRunner.kt
@@ -152,7 +152,7 @@ abstract class GenericTestRunner: ITestRunnerContributor {
         }
 
         // JVM flags from the interceptors (these overwrite flags instead of just adding to the list)
-        var result = ArrayList(jvmFlags + jvmFlagsFromContributors)
+        val result = ArrayList(jvmFlags + jvmFlagsFromContributors)
         pluginInfo.testJvmFlagInterceptors.forEach {
             val newFlags = it.testJvmFlagsFor(project, context, result)
             result.clear()