1 /*
 2  * Copyright (c) 2021, 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.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 import jdk.test.lib.Asserts;
27 
28 import java.util.concurrent.atomic.AtomicReference;
29 
30 /**
31  * @test JNIMonitor
32  * @summary Tests that JNI monitors works correctly for native threads
33  * @library /test/lib
34  * @compile --enable-preview -source ${jdk.version} JNIMonitor.java
35  * @run main/native/othervm --enable-preview JNIMonitor
36  */
37 
38 public class JNIMonitor {
39 
40     // straight-forward interface to JNI monitor functions
41     static native int monitorEnter(Object o);
42     static native int monitorExit(Object o);
43     static {
44         System.loadLibrary("JNIMonitor");
45     }
46 
47     public static void main(String[] args) throws Throwable {
48         final Object monitor = new Object();
49         final AtomicReference<Throwable> exception = new AtomicReference();
50         Thread.ofVirtual().start(() -> {
51             try {
52                 int res = monitorEnter(monitor);
53                 Asserts.assertTrue(res == 0, "monitorEnter should return 0.");
54                 Thread.yield();
55                 res = monitorExit(monitor);
56                 Asserts.assertTrue(res == 0, "monitorExit should return 0.");
57             } catch (Throwable t) {
58                 exception.set(t);
59             }
60         }).join();
61         if (exception.get() != null) {
62             throw exception.get();
63         }
64     }
65 }