diff --git a/biopet.wdl b/biopet.wdl
index 28cd210e9ed748ec14ed70ba73f2403a977355d3..7a16368f4f6faaf6e17945115784ac0ded1b4076 100644
--- a/biopet.wdl
+++ b/biopet.wdl
@@ -3,7 +3,7 @@
 
 task BaseCounter {
     String? preCommand
-    String? toolJar
+    File? toolJar
     File bam
     File bamIndex
     File refFlat
@@ -72,7 +72,7 @@ task BaseCounter {
 }
 
 task ExtractAdaptersFastqc {
-    String? toolJar
+    File? toolJar
     File inputFile
     String outputDir
     String? adapterOutputFilePath = outputDir + "/adapter.list"
@@ -122,7 +122,7 @@ task FastqSplitter {
     String? preCommand
     File inputFastq
     Array[String] outputPaths
-    String? toolJar
+    File? toolJar
 
     Float? memory
     Float? memoryMultiplier
@@ -162,7 +162,7 @@ task FastqSync {
     File in2
     String out1path
     String out2path
-    String? toolJar
+    File? toolJar
     
     Float? memory
     Float? memoryMultiplier
@@ -196,7 +196,7 @@ task FastqSync {
 }
 
 task SampleConfig {
-    String? toolJar
+    File? toolJar
     String? preCommand
     Array[File]+ inputFiles
     String keyFilePath
@@ -244,7 +244,7 @@ task ScatterRegions {
     File refFasta
     File refDict
     String outputDirPath
-    String? toolJar
+    File? toolJar
     Int? scatterSize
     File? regions