src/hotspot/share/classfile/classLoaderData.hpp

Access_GetLoadedClasses

   friend class ClassLoaderDataGraph;
   friend class ClassLoaderDataGraphKlassIteratorAtomic;
   friend class ClassLoaderDataGraphKlassIteratorStatic;
   friend class ClassLoaderDataGraphMetaspaceIterator;
   friend class InstanceKlass;
+  friend class Klass;
   friend class MetaDataFactory;
   friend class Method;
 
   static ClassLoaderData * _the_null_class_loader_data;