diff --git a/src/share/vm/classfile/defaultMethods.cpp b/src/share/vm/classfile/defaultMethods.cpp
index 4e43d7fd323a307ca11d1d8611927986488b41f2..1977b07ea105d3be4ab2926bf792eb1b83772d82 100644
--- a/src/share/vm/classfile/defaultMethods.cpp
+++ b/src/share/vm/classfile/defaultMethods.cpp
@@ -348,7 +348,7 @@ class MethodFamily : public ResourceObj {
 
   void disqualify_method(Method* method) {
     int* index = _member_index.get(method);
-    assert(index != NULL && *index >= 0 && *index < _members.length(), "bad index");
+    guarantee(index != NULL && *index >= 0 && *index < _members.length(), "bad index");
     _members.at(*index).second = DISQUALIFIED;
   }