diff --git a/nj2k/src/org/jetbrains/kotlin/nj2k/conversions/ModalityConversion.kt b/nj2k/src/org/jetbrains/kotlin/nj2k/conversions/ModalityConversion.kt
index 084bdb6e733..55e2ef0a022 100644
--- a/nj2k/src/org/jetbrains/kotlin/nj2k/conversions/ModalityConversion.kt
+++ b/nj2k/src/org/jetbrains/kotlin/nj2k/conversions/ModalityConversion.kt
@@ -16,6 +16,7 @@ class ModalityConversion(private val context: ConversionContext) : RecursiveAppl
         when (element) {
             is JKClass -> processClass(element)
             is JKJavaMethod -> processMethod(element)
+            is JKField -> processField(element)
         }
         return recurse(element)
     }
@@ -51,4 +52,11 @@ class ModalityConversion(private val context: ConversionContext) : RecursiveAppl
             else -> method.modality
         }
     }
+
+    private fun processField(field: JKField) {
+        val containingClass = field.parentOfType<JKClass>()!!
+        if (containingClass.classKind == JKClass.ClassKind.INTERFACE) {
+            field.modality = Modality.FINAL
+        }
+    }
 }
\ No newline at end of file