jdk-24/test/jdk/java/lang/Thread/jni/AttachCurrentThread/ExplicitAttach.java
2022-06-22 07:48:14 +00:00

63 lines
2.0 KiB
Java

/*
* Copyright (c) 2022, 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.
*/
import java.util.concurrent.CountDownLatch;
/**
* Test native threads attaching to the VM with JNI AttachCurrentThread.
*/
public class ExplicitAttach {
private static volatile CountDownLatch latch;
public static void main(String[] args) throws Exception {
int threadCount;
if (args.length > 0) {
threadCount = Integer.parseInt(args[0]);
} else {
threadCount = 2;
}
latch = new CountDownLatch(threadCount);
// start the threads and wait for the threads to call home
startThreads(threadCount);
latch.await();
}
/**
* Invoked by attached threads.
*/
private static void callback() {
System.out.println(Thread.currentThread());
latch.countDown();
}
/**
* Start n native threads that attach to the VM and invoke callback.
*/
private static native void startThreads(int n);
static {
System.loadLibrary("ExplicitAttach");
}
}