--- old/src/hotspot/share/oops/instanceKlass.hpp	2018-08-23 18:48:22.447358608 -0400
+++ new/src/hotspot/share/oops/instanceKlass.hpp	2018-08-23 18:48:22.018898651 -0400
@@ -41,6 +41,7 @@
 #include "utilities/align.hpp"
 #include "utilities/macros.hpp"
 #if INCLUDE_JFR
+#include "utilities/ticks.hpp"
 #include "jfr/support/jfrKlassExtension.hpp"
 #endif
 
@@ -142,6 +143,11 @@
  private:
   static InstanceKlass* allocate_instance_klass(const ClassFileParser& parser, TRAPS);
 
+#if INCLUDE_JFR
+  // JFR Class unloading timestamp
+  static Ticks _class_unload_time;
+#endif
+
  protected:
   // If you add a new field that points to any metaspace object, you
   // must add this field to InstanceKlass::metaspace_pointers_do().
@@ -426,6 +432,11 @@
     _transitive_interfaces = a;
   }
 
+#if INCLUDE_JFR
+  static void set_class_unload_time(Ticks ticks) { _class_unload_time = ticks; }
+  static Ticks class_unload_time() { return _class_unload_time; }
+#endif
+
  private:
   friend class fieldDescriptor;
   FieldInfo* field(int index) const { return FieldInfo::from_field_array(_fields, index); }