--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/z/ZHash.java	Tue Jun 12 17:40:28 2018 +0200
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2017, 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.
+ *
+ */
+
+package sun.jvm.hotspot.gc.z;
+
+class ZHash {
+    private static long uint32(long value) {
+        return value & 0xFFFFFFFFL;
+    }
+
+    static long uint32_to_uint32(long key) {
+        key = uint32(~key + (key << 15));
+        key = uint32(key ^ (key >> 12));
+        key = uint32(key + (key << 2));
+        key = uint32(key ^ (key >> 4));
+        key = uint32(key * 2057);
+        key = uint32(key ^ (key >> 16));
+        return key;
+    }
+}