diff --git a/idea/src/org/jetbrains/kotlin/idea/conversion/copy/KotlinFilePasteProvider.kt b/idea/src/org/jetbrains/kotlin/idea/conversion/copy/KotlinFilePasteProvider.kt
index 586c924caee..a8c0ab49202 100644
--- a/idea/src/org/jetbrains/kotlin/idea/conversion/copy/KotlinFilePasteProvider.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/conversion/copy/KotlinFilePasteProvider.kt
@@ -55,11 +55,14 @@ class KotlinFilePasteProvider : PasteProvider {
         val ideView = ideView(dataContext)
         if (project == null || ideView == null || ideView.directories.isEmpty()) return false
         val text = CopyPasteManager.getInstance().getContents<String>(DataFlavor.stringFlavor) ?: return false
-        if (text.contains(";\n")) return false //Optimisation for Java. Kotlin doesn't need that...
+        //todo: KT-25329, to remove these heuristics
+        if (text.contains(";\n") ||
+            ((text.contains("public interface") || text.contains("public class")) &&
+                    !text.contains("fun "))) return false //Optimisation for Java. Kotlin doesn't need that...
         val file = KtPsiFactory(project).createFile(text)
         return !PsiTreeUtil.hasErrorElements(file)
     }
 
     private fun project(dataContext: DataContext): Project? = CommonDataKeys.PROJECT.getData(dataContext)
     private fun ideView(dataContext: DataContext): IdeView? = LangDataKeys.IDE_VIEW.getData(dataContext)
-}
\ No newline at end of file
+}