--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/test/jdk/jfr/api/recording/event/TestReEnableMultiple.java	2019-01-29 11:02:06.292284218 +0800
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2018, 2019, 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.api.recording.event;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Random;
+
+import jdk.jfr.EventType;
+import jdk.jfr.Recording;
+import jdk.jfr.consumer.RecordedEvent;
+import jdk.testlibrary.Asserts;
+import jdk.testlibrary.jfr.EventNames;
+import jdk.testlibrary.jfr.Events;
+import jdk.testlibrary.jfr.SimpleEvent;
+import jdk.testlibrary.jfr.SimpleEventHelper;
+
+/*
+ * @test
+ * @summary Enable, disable, enable event during recording.
+ * @key jfr
+ * @library /lib/testlibrary
+ * @run main/othervm jdk.jfr.api.recording.event.TestReEnableMultiple
+ */
+public class TestReEnableMultiple {
+    private static final String EVENT_PATH = EventNames.FileWrite;
+    private static final Random rand = new Random(0);
+
+    public static void main(String[] args) throws Throwable {
+        Recording rA = new Recording();
+        Recording rB = new Recording();
+
+        final Path path = Paths.get(".", "dummy.txt").toAbsolutePath();
+        rA.start();
+        rB.start();
+
+        SimpleEventHelper.enable(rA, false);
+        SimpleEventHelper.enable(rA, false);
+
+        int expectedMyEvents = 0;
+        int expectedIoEvents = 0;
+        for (int i = 0; i < 20; ++i) {
+            SimpleEventHelper.createEvent(i);
+            if (isMyEventEnabled(rA, rB)) {
+                expectedMyEvents++;
+                System.out.println("Expect MyEvent.id " + i);
+            }
+
+            Files.write(path, "A".getBytes());
+            if (isIoEnabled(rA, rB)) {
+                expectedIoEvents++;
+            }
+
+            for (int j = 0; j < 4; ++j) {
+                Recording r = (rand.nextInt(2) == 0) ? rA : rB;
+                updateSettings(r);
+            }
+        }
+
+        rA.stop();
+        rB.stop();
+
+        verifyEventCount(rA, expectedMyEvents, expectedIoEvents, path);
+        verifyEventCount(rB, expectedMyEvents, expectedIoEvents, path);
+
+        rA.close();
+        rB.close();
+    }
+
+    private static void verifyEventCount(Recording r, int expectedMyEvents, int expectedIoEvents, Path path) throws Exception {
+        int actualMyEvents = 0;
+        int actualIoEvents = 0;
+        for (RecordedEvent event : Events.fromRecording(r)) {
+            if (Events.isEventType(event, EVENT_PATH)) {
+                if (path.toString().equals(Events.assertField(event, "path").getValue())) {
+                    actualIoEvents++;
+                }
+            } else {
+                Asserts.assertTrue(Events.isEventType(event, SimpleEvent.class.getName()));
+                System.out.println("Got MyEvent.id=" + Events.assertField(event, "id").getValue());
+                actualMyEvents++;
+            }
+        }
+        System.out.printf("MyEvents: expected=%d, actual=%d%n", expectedMyEvents, actualMyEvents);
+        System.out.printf("IoEvents: expected=%d, actual=%d%n", expectedIoEvents, actualIoEvents);
+        Asserts.assertEquals(expectedMyEvents, actualMyEvents, "Wrong number of MyEvents");
+        Asserts.assertEquals(expectedIoEvents, actualIoEvents, "Wrong number of IoEvents");
+    }
+
+    private static void updateSettings(Recording r) {
+        boolean doEnable = rand.nextInt(3) == 0; // Disable 2 of 3, since event
+                                                 // is enabled by union of
+                                                 // recordings.
+        boolean doMyEvent = rand.nextInt(2) == 0;
+        if (doMyEvent) {
+            SimpleEventHelper.enable(r, doEnable);
+        } else {
+            if (doEnable) {
+                r.enable(EVENT_PATH).withoutStackTrace();
+            } else {
+                r.disable(EVENT_PATH);
+            }
+        }
+    }
+
+    private static boolean isMyEventEnabled(Recording rA, Recording rB) {
+        long eventTypeId = EventType.getEventType(SimpleEvent.class).getId();
+        String settingName = eventTypeId + "#enabled";
+        return isEnabled(rA, settingName) || isEnabled(rB, settingName);
+    }
+
+    private static boolean isIoEnabled(Recording rA, Recording rB) {
+        String settingName = EVENT_PATH + "#enabled";
+        return isEnabled(rA, settingName) || isEnabled(rB, settingName);
+    }
+
+    private static boolean isEnabled(Recording r, String settingName) {
+        // System.out.printf("R(%s) %s=%s%n", r.getName(), settingName,
+        // r.getSettings().get(settingName));
+        return Boolean.parseBoolean(r.getSettings().get(settingName));
+    }
+}