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/*
* Copyright (c) 2025, 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.
*/
/*
* @test
* @bug 8349206
* @summary j.u.l.Handler classes create deadlock risk via synchronized publish() method.
* @modules java.base/sun.util.logging
* java.logging
* @build java.logging/java.util.logging.TestStreamHandler
* @run main/othervm StreamHandlerLockingTest
*/
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.TestStreamHandler;
public class StreamHandlerLockingTest {
static class TestFormatter extends Formatter {
final Handler handler;
TestFormatter(Handler handler) {
this.handler = handler;
}
@Override
public String format(LogRecord record) {
if (Thread.holdsLock(handler)) {
throw new AssertionError("format() was called with handler locked (bad).");
}
return record.getMessage() + "\n";
}
@Override
public String getHead(Handler h) {
// This is currently true, and not easy to make unsynchronized.
if (!Thread.holdsLock(handler)) {
throw new AssertionError("getHead() expected to be called with handler locked.");
}
return "--HEAD--\n";
}
@Override
public String getTail(Handler h) {
// This is currently true, and not easy to make unsynchronized.
if (!Thread.holdsLock(handler)) {
throw new AssertionError("getTail() expected to be called with handler locked.");
}
return "--TAIL--\n";
}
}
private static final String EXPECTED_LOG =
String.join("\n", "--HEAD--", "Hello World", "Some more logging...", "And we're done!", "--TAIL--", "");
public static void main(String[] args) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
TestStreamHandler handler = new TestStreamHandler(out);
TestFormatter formatter = new TestFormatter(handler);
handler.setFormatter(formatter);
handler.publish(log("Hello World"));
handler.publish(log("Some more logging..."));
handler.publish(log("And we're done!"));
handler.close();
// Post write callback should have happened once per publish call (with lock held).
if (handler.callbackCount != 3) {
throw new AssertionError("Unexpected callback count: " + handler.callbackCount);
}
String logged = out.toString("UTF-8");
if (!EXPECTED_LOG.equals(logged)) {
throw new AssertionError("Unexpected log contents: " + logged);
}
}
static LogRecord log(String msg) {
return new LogRecord(Level.INFO, msg);
}
}
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