diff --git a/lib/src/main/java/com/diffplug/spotless/java/PalantirJavaFormatStep.java b/lib/src/main/java/com/diffplug/spotless/java/PalantirJavaFormatStep.java
index a5474d549b..89673787d6 100644
--- a/lib/src/main/java/com/diffplug/spotless/java/PalantirJavaFormatStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/java/PalantirJavaFormatStep.java
@@ -60,6 +60,7 @@ private static final class State implements Serializable {
 		private final String formatterVersion;
 
 		State(JarState jarState, String formatterVersion) {
+			ModuleHelper.doOpenInternalPackagesIfRequired();
 			this.jarState = jarState;
 			this.formatterVersion = formatterVersion;
 		}