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*
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* 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
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*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
/*
* @test
* @bug 6417044
* @summary Test deadlock in MBeanRegistration.postRegister method
* @author Eamonn McManus, Daniel Fuchs
* @run clean PostRegisterDeadlockTest
* @run build PostRegisterDeadlockTest
* @run main PostRegisterDeadlockTest
*/
import java.lang.Thread.State;
import java.util.concurrent.*;
import javax.management.*;
public class PostRegisterDeadlockTest {
public static interface BlibbyMBean {}
public static class Blibby implements BlibbyMBean, MBeanRegistration {
public Blibby(MBeanServer mbs, ObjectName otherName) {
this.mbs = mbs;
this.otherName = otherName;
}
public ObjectName preRegister(MBeanServer mbs, ObjectName on) {
return on;
}
public void preDeregister() {}
public void postRegister(Boolean done) {
// If no other MBean was registered
// do nothing.
//
if (otherName == null) return;
// Check that we can unregister
// other MBean
try {
Thread t = new Thread() {
public void run() {
try {
try {
mbs.unregisterMBean(otherName);
} catch (InstanceNotFoundException x) {
// Race condition!
System.out.println(otherName+
" was unregistered by main thread.");
}
} catch (Throwable e) {
e.printStackTrace(System.out);
fail(e.toString());
}
}
};
t.start();
t.join(5000L);
if (t.isAlive()) {
if (t.getState().equals(State.BLOCKED))
fail("Deadlock detected");
else
fail("Test not conclusive: "+
"Thread is alive but not blocked.");
}
} catch (Throwable e) {
e.printStackTrace(System.out);
fail(e.toString());
}
}
public void postDeregister() {}
private final MBeanServer mbs;
private final ObjectName otherName;
}
public static void main(String[] args) throws Exception {
String previous = null;
MBeanServer mbs = MBeanServerFactory.newMBeanServer();
ObjectName on1 = new ObjectName("a:type=Blibby,name=\"1\"");
ObjectName on2 = new ObjectName("a:type=Blibby,name=\"2\"");
// Test 1:
// 1 MBean is registered with on1
// Another MBean is registered with on1, postRegister(FALSE) is
// called, and the second MBean attempts to unregister first MBean in
// postRegister:
// postRegister starts a thread which unregisters the first MBean:
// this must not deadlock
//
System.out.println("\n**** TEST #1 ****\n");
System.out.println("Registering Blibby #1 with name: " + on1);
mbs.registerMBean(new Blibby(mbs, null), on1);
try {
System.out.println("Registering Blibby #2 with same name: " + on1);
mbs.registerMBean(new Blibby(mbs, on1), on1);
} catch (InstanceAlreadyExistsException x) {
System.out.println("Received expected exception: " + x);
}
if (mbs.isRegistered(on1)) {
try {
mbs.unregisterMBean(on1);
if (failure == null)
fail(on1+" should have been unregistered");
} catch (InstanceNotFoundException x) {
// Race condition!
System.out.println(on1+" was unregistered by mbean thread.");
}
} else {
System.out.println(on1+" was correctly unregistered.");
}
if (failure == previous)
System.out.println("\n**** TEST #1 PASSED ****\n");
previous = failure;
// Test 2:
// 1 MBean is registered with on1
// Another MBean is registered with on2, postRegister(TRUE) is
// called, and the second MBean attempts to unregister first MBean in
// postRegister:
// postRegister starts a thread which unregisters the first MBean:
// this must not deadlock
//
System.out.println("\n**** TEST #2 ****\n");
System.out.println("Registering Blibby #1 with name: " + on1);
mbs.registerMBean(new Blibby(mbs, null), on1);
System.out.println("Registering Blibby #2 with other name: " + on2);
mbs.registerMBean(new Blibby(mbs, on1), on2);
if (mbs.isRegistered(on1)) {
try {
mbs.unregisterMBean(on1);
if (failure == null)
fail(on1+" should have been unregistered");
} catch (InstanceNotFoundException x) {
// Race condition!
System.out.println(on1+" was unregistered by mbean thread.");
}
} else {
System.out.println(on1+" was correctly unregistered.");
}
System.out.println("unregistering "+on2);
mbs.unregisterMBean(on2);
if (failure == previous)
System.out.println("\n**** TEST #2 PASSED ****\n");
previous = failure;
if (failure == null)
System.out.println("OK: Test passed");
else
throw new Exception("TEST FAILED: " + failure);
}
private static void fail(String why) {
System.out.println("FAILED: " + why);
failure = (failure == null)?why:(failure+",\n"+why);
}
private static volatile String failure;
}