diff --git a/j2k/src/org/jetbrains/kotlin/j2k/JavaToKotlinConverter.kt b/j2k/src/org/jetbrains/kotlin/j2k/JavaToKotlinConverter.kt
index 7a7921134a3..6fc1259903f 100644
--- a/j2k/src/org/jetbrains/kotlin/j2k/JavaToKotlinConverter.kt
+++ b/j2k/src/org/jetbrains/kotlin/j2k/JavaToKotlinConverter.kt
@@ -349,7 +349,7 @@ class JavaToKotlinConverter(
         override fun isModal() = delegate.isModal
         override fun getModalityState() = delegate.modalityState
 
-        override fun setModalityProgress(modalityProgress: ProgressIndicator) {
+        override fun setModalityProgress(modalityProgress: ProgressIndicator?) {
             delegate.setModalityProgress(modalityProgress)
         }