--- /dev/null	2020-01-02 04:43:18.583999853 +0000
+++ new/test/jdk/jfr/event/gc/objectcount/ObjectCountEventVerifier.java	2020-01-30 06:33:27.124002265 +0000
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2013, 2018, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 jdk.jfr.event.gc.objectcount;
+
+import java.util.List;
+import java.util.HashMap;
+
+import jdk.jfr.consumer.RecordedEvent;
+import jdk.test.lib.Asserts;
+import jdk.test.lib.jfr.Events;
+
+class Foo {
+}
+
+class Constants {
+    public static final int oneMB = 1048576;
+}
+
+public class ObjectCountEventVerifier {
+    public static Foo[] foos;
+
+    public static void createTestData() {
+        foos = new Foo[Constants.oneMB];
+    }
+
+    public static void verify(List<RecordedEvent> objectCountEvents) throws Exception {
+        Asserts.assertFalse(objectCountEvents.isEmpty(), "Expected at least one object count event");
+        // Object count events should be sent only for those classes which instances occupy over 0.5%
+        // of the heap. Therefore there can't be more than 200 events
+        Asserts.assertLessThanOrEqual(objectCountEvents.size(), 200, "Expected at most 200 object count events");
+
+        HashMap<String, Long> numInstancesOfClass = new HashMap<String, Long>();
+        HashMap<String, Long> sizeOfInstances = new HashMap<String, Long>();
+
+        for (RecordedEvent event : objectCountEvents) {
+            String className = Events.assertField(event, "objectClass.name").notEmpty().getValue();
+            long count = Events.assertField(event, "count").atLeast(0L).getValue();
+            long totalSize = Events.assertField(event, "totalSize").atLeast(1L).getValue();
+            System.out.println(className);
+            numInstancesOfClass.put(className, count);
+            sizeOfInstances.put(className, totalSize);
+        }
+        System.out.println(numInstancesOfClass);
+        final String fooArrayName = "[Ljdk/jfr/event/gc/objectcount/Foo;";
+        Asserts.assertTrue(numInstancesOfClass.containsKey(fooArrayName), "Expected an event for the Foo array");
+        Asserts.assertEquals(sizeOfInstances.get(fooArrayName), expectedFooArraySize(Constants.oneMB), "Wrong size of the Foo array");
+    }
+
+    private static long expectedFooArraySize(long count) {
+        boolean runsOn32Bit = System.getProperty("sun.arch.data.model").equals("32");
+        int bytesPerWord = runsOn32Bit ? 4 : 8;
+        int objectHeaderSize = bytesPerWord * 3; // length will be aligned on 64 bits
+        int alignmentInOopArray = runsOn32Bit ? 4 : 0;
+        int ptrSize = bytesPerWord;
+        return objectHeaderSize + alignmentInOopArray + count * ptrSize;
+    }
+}