diff --git a/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java b/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java
index 6c1f9220644d..99a45d55fc54 100644
--- a/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java
+++ b/java/java-impl/src/com/intellij/codeInsight/folding/impl/JavaFoldingBuilder.java
@@ -26,6 +26,7 @@ import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.FoldingGroup;
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.project.IndexNotReadyException;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
@@ -715,7 +716,12 @@ public class JavaFoldingBuilder extends CustomFoldingBuilder implements DumbAwar
       }
     }
 
-    return !OverrideImplementUtil.getMethodSignaturesToImplement(baseClass).isEmpty();
+    try {
+      return !OverrideImplementUtil.getMethodSignaturesToImplement(baseClass).isEmpty();
+    }
+    catch (IndexNotReadyException e) {
+      return false;
+    }
   }
 
   private static boolean addToFold(List<FoldingDescriptor> list, PsiElement elementToFold, Document document, boolean allowOneLiners) {