Hi all, I'm looking at an issue that I'm experiencing (with Felix 4.6.1/Java 7) where the ServiceRegsitry.getService() [1] method seems to be in an endless loop. It doesn't happen very often, but when it does happen the thread executing getService() seems to never exit that method apparently switch between the following two states:
1: Thread 22059: (state = IN_VM) - java.lang.Object.wait(long) @bci=0 (Compiled frame; information may be imprecise) - java.lang.Object.wait() @bci=2, line=503 (Compiled frame) - org.apache.felix.framework.ServiceRegistry.getService(org.osgi.framework.Bundle, org.osgi.framework.ServiceReference, boolean) @bci=86, line=313 (Compiled frame) 2: Thread 22059: (state = IN_VM) - java.lang.Throwable.fillInStackTrace(int) @bci=0 (Compiled frame; information may be imprecise) - java.lang.Throwable.fillInStackTrace() @bci=16, line=783 (Compiled frame) - java.lang.Throwable.<init>() @bci=24, line=250 (Compiled frame) - java.lang.Exception.<init>() @bci=1, line=54 (Compiled frame) - java.lang.InterruptedException.<init>() @bci=1, line=57 (Compiled frame) - java.lang.Object.wait(long) @bci=0 (Compiled frame) - java.lang.Object.wait() @bci=2, line=503 (Compiled frame) - org.apache.felix.framework.ServiceRegistry.getService(org.osgi.framework.Bundle, org.osgi.framework.ServiceReference, boolean) @bci=86, line=313 (Compiled frame) Even though the thread is executing wait() all of the other Felix SR-accessing threads are blocked on the Service Registry lock. The net effect is that any operation on the Service Registry is blocked. There is one thing that I don't understand and that is that in the above frames the lock should really be released, as the code is in wait(). However, it seems like the lock is still held because none of the other threads are getting access to the Service Registry. For example another such thread is the following which is actually about to decrease the usage count on the service and then call notifyAll(): Thread 48643: (state = BLOCKED) - org.apache.felix.framework.ServiceRegistry.getService(org.osgi.framework.Bundle, org.osgi.framework.ServiceReference, boolean) @bci=241, line=367 (Compiled frame) - org.apache.felix.framework.util.EventDispatcher.filterListenersUsingHooks(org.osgi.framework.ServiceEvent, org.osgi.framework.launch.Framework, java.util.Map) @bci=349, line=618 (Compiled frame) - org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(org.osgi.framework.ServiceEvent, java.util.Dictionary, org.osgi.framework.launch.Framework) @bci=33, line=542 (Interpreted frame) - org.apache.felix.framework.Felix.fireServiceEvent(org.osgi.framework.ServiceEvent, java.util.Dictionary) @bci=7, line=4547 (Compiled frame) - org.apache.felix.framework.Felix.access$000(org.apache.felix.framework.Felix, org.osgi.framework.ServiceEvent, java.util.Dictionary) @bci=3, line=106 (Compiled frame) - org.apache.felix.framework.Felix$1.serviceChanged(org.osgi.framework.ServiceEvent, java.util.Dictionary) @bci=6, line=436 (Compiled frame) - org.apache.felix.framework.ServiceRegistry.unregisterService(org.osgi.framework.Bundle, org.osgi.framework.ServiceRegistration) @bci=100, line=165 (Compiled frame) - org.apache.felix.framework.ServiceRegistrationImpl.unregister() @bci=52, line=140 (Interpreted frame) I just don't understand why all the other threads are blocked on the service registry. I'm probably missing something simple, so would be grateful if someone else has an idea. Many thanks, David [1] http://svn.apache.org/repos/asf/felix/releases/org.apache.felix.framework-4.6.1/src/main/java/org/apache/felix/framework/ServiceRegistry.java
