diff -r 6515a96809a1 -r a0d4e61acb6b src/hotspot/share/classfile/systemDictionary.hpp
--- a/src/hotspot/share/classfile/systemDictionary.hpp	Thu May 30 10:29:55 2019 +0800
+++ b/src/hotspot/share/classfile/systemDictionary.hpp	Thu May 30 12:45:02 2019 -0700
@@ -214,6 +214,9 @@
   do_klass(Integer_klass,                               java_lang_Integer                                     ) \
   do_klass(Long_klass,                                  java_lang_Long                                        ) \
                                                                                                                 \
+  /* force inline of iterators */                                                                               \
+  do_klass(Iterator_klass,                              java_util_Iterator                                    ) \
+                                                                                                                \
   /*end*/