--- /dev/null	2020-05-08 10:28:18.126332474 +0200
+++ new/src/hotspot/share/gc/z/zUnmapper.hpp	2020-06-01 07:12:31.533012059 +0200
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef SHARE_GC_Z_ZUNMAPPER_HPP
+#define SHARE_GC_Z_ZUNMAPPER_HPP
+
+#include "gc/shared/concurrentGCThread.hpp"
+
+class ZUnmapper : public ConcurrentGCThread {
+protected:
+  virtual void run_service();
+  virtual void stop_service();
+
+public:
+  ZUnmapper();
+};
+
+#endif // SHARE_GC_Z_ZUNMAPPER_HPP