diff --git a/build.gradle b/build.gradle
index 952a16eb13af2dbef5a10e22991fb0570b460d95..1d0c641eb4ab30b6544c6edbeb1890438d8cbf08 100644
--- a/build.gradle
+++ b/build.gradle
@@ -103,7 +103,7 @@ jar {
     duplicatesStrategy = DuplicatesStrategy.WARN
 }
 
-def relastFiles = ['./src/main/jastadd/common/MotionGrammar.relast', './src/main/jastadd/load/LoadWorld.relast', './src/main/jastadd/cleanup/RobotWorld.relast', './src/main/jastadd/load/LoadUnload.relast', './src/main/jastadd/cleanup/Cleanup.relast']
+def relastFiles = ['./src/gen/jastadd/MotionGrammar.relast', './src/main/jastadd/load/LoadWorld.relast', './src/gen/jastadd/RobotWorld.relast', './src/main/jastadd/load/LoadUnload.relast', './src/main/jastadd/cleanup/Cleanup.relast']
 def loadingRelastFiles = ['./src/main/jastadd/common/MotionGrammar.relast', './src/main/jastadd/load/LoadWorld.relast', './src/main/jastadd/load/LoadUnload.relast']
 def cleaningRelastFiles = ['./src/main/jastadd/common/MotionGrammar.relast', './src/main/jastadd/cleanup/RobotWorld.relast', './src/main/jastadd/cleanup/Cleanup.relast']
 def grammarPrefix = './src/gen/jastadd/MotionGrammar'
@@ -171,8 +171,9 @@ task relastToJastAdd(type: JavaExec) {
             '--useJastAddNames',
             '--listClass=java.util.ArrayList',
             "--jastAddList=${jastAddListName}",
-            "--resolverHelper",
-            '--file'
+            '--resolverHelper',
+            '--file',
+            '--serializer=jackson'
     args relastFiles
 
     inputs.files relastFiles