1 /*
 2  * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 package jdk.jfr.event.oldobject;
24 
25 import java.util.ArrayList;
26 import java.util.List;
27 
28 import jdk.jfr.Recording;
29 import jdk.jfr.consumer.RecordedEvent;
30 import jdk.jfr.internal.test.WhiteBox;
31 import jdk.test.lib.jfr.EventNames;
32 import jdk.test.lib.jfr.Events;
33 
34 /**
35  * @test
36  * @requires vm.flagless
37  * @requires vm.hasJFR
38  * @library /test/lib /test/jdk
39  * @modules jdk.jfr/jdk.jfr.internal.test
40  * @run main/othervm -XX:TLABSize=2k jdk.jfr.event.oldobject.TestCircularReference
41  */
42 public class TestCircularReference {
43 
44     static class TestCircularReferrer {
45         // Allocate array to trigger sampling code path for interpreter / c1
46         final byte[] leak = new byte[1_0000_000];
47         TestCircularReferrer reference;
48 
49         public void setReference(TestCircularReferrer reference) {
50             this.reference = reference;
51         }
52     }
53 
54     public final static List<Object> referenceHolder = new ArrayList<>(OldObjects.MIN_SIZE);
55 
56     public static void main(String[] args) throws Exception {
57         WhiteBox.setWriteAllObjectSamples(true);
58 
59         try (Recording r = new Recording()) {
60             r.enable(EventNames.OldObjectSample).with("cutoff", "infinity").withStackTrace();
61             r.start();
62 
63             TestCircularReferrer a = new TestCircularReferrer();
64             TestCircularReferrer b = new TestCircularReferrer();
65             TestCircularReferrer c = new TestCircularReferrer();
66             a.setReference(b);
67             b.setReference(c);
68             c.setReference(a);
69             referenceHolder.add(a);
70 
71             TestCircularReferrer selfReflector = new TestCircularReferrer();
72             selfReflector.setReference(selfReflector);
73             referenceHolder.add(selfReflector);
74 
75             r.stop();
76 
77             List<RecordedEvent> events = Events.fromRecording(r);
78             if (events.isEmpty()) {
79                 throw new AssertionError("Expected Old Object Sample events!");
80             }
81         }
82     }
83 }