--- /dev/null	2020-05-08 10:28:18.126332474 +0200
+++ new/test/hotspot/jtreg/gc/z/TestNoUncommit.java	2020-08-18 12:52:03.562525428 +0200
@@ -0,0 +1,63 @@
+/*
+ * 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.
+ */
+
+package gc.z;
+
+/*
+ * @test TestNoUncommit
+ * @requires vm.gc.Z & !vm.graal.enabled
+ * @summary Test ZGC uncommit unused memory disabled
+ * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+heap=debug,gc+stats=off -Xms512M -Xmx512M -XX:ZUncommitDelay=1 gc.z.TestNoUncommit
+ * @run main/othervm -XX:+UseZGC -Xlog:gc*,gc+heap=debug,gc+stats=off -Xms128M -Xmx512M -XX:ZUncommitDelay=1 -XX:-ZUncommit gc.z.TestNoUncommit
+ */
+
+public class TestNoUncommit {
+    private static final int allocSize = 200 * 1024 * 1024; // 200M
+    private static volatile Object keepAlive = null;
+
+    private static long capacity() {
+        return Runtime.getRuntime().totalMemory();
+    }
+
+    public static void main(String[] args) throws Exception {
+        System.out.println("Allocating");
+        keepAlive = new byte[allocSize];
+        final var afterAlloc = capacity();
+
+        System.out.println("Reclaiming");
+        keepAlive = null;
+        System.gc();
+
+        // Wait longer than the uncommit delay (which is 1 second)
+        Thread.sleep(5 * 1000);
+
+        final var afterDelay = capacity();
+
+        // Verify
+        if (afterAlloc > afterDelay) {
+            throw new Exception("Should not uncommit");
+        }
+
+        System.out.println("Success");
+    }
+}