diff --git a/java/java-impl/src/com/intellij/codeInsight/generation/OverrideImplementUtil.java b/java/java-impl/src/com/intellij/codeInsight/generation/OverrideImplementUtil.java
index f9314080f647..3a4b690af4e5 100644
--- a/java/java-impl/src/com/intellij/codeInsight/generation/OverrideImplementUtil.java
+++ b/java/java-impl/src/com/intellij/codeInsight/generation/OverrideImplementUtil.java
@@ -537,6 +537,7 @@ public class OverrideImplementUtil {
     final List<PsiMethodMember> selectedElements = chooser.getSelectedElements();
     if (selectedElements == null || selectedElements.isEmpty()) return;
 
+    LOG.assertTrue(aClass.isValid());
     new WriteCommandAction(project, aClass.getContainingFile()) {
       protected void run(final Result result) throws Throwable {
         overrideOrImplementMethodsInRightPlace(editor, aClass, selectedElements, chooser.isCopyJavadoc(), chooser.isInsertOverrideAnnotation());