[FELIX-6067] ClassLoading and getService can fail unpredictably due to interrupts

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: framework-6.0.2
• Fix Version/s: framework-6.0.3
• Component/s: Framework
• Assignee: Karl Pauls
• Reporter: Robert Munteanu
• Created: 22/Feb/19 11:56
• Updated: 02/May/19 08:25
• Resolved: 22/Feb/19 22:40

Description

I noticed an intermittent issue with our Felix-based app (Apache Sling). The flows seems to be the following:

(thread 1)

• component C is started
• component C invokes method on class K1
• class K1 is first accessed now and runs class initializers
• K1 static initializer calls method from class K2
• class K2 loading is triggered

(thread 2)

• component C is stopped ( I think due to configuration coming in )

(thread 1)

• during class loading of K2 a RuntimeException is thrown, resulting in all calls to K1 leading to NoClassDefFoundError

At this point although the error should be transient the component is unusable since one of the classes it uses is not available.

For the record, the stack trace which causes this is

21.02.2019 14:50:50.292 *ERROR* [Apache Sling Repository Startup Thread #1] org.apache.sling.jcr.oak.server.internal.OakSlingRepositoryManager start: Uncaught Throwable trying to access Repository, calling stopRepository()
java.lang.ExceptionInInitializerError: null
        at org.apache.sling.jcr.oak.server.internal.OakSlingRepositoryManager.acquireRepository(OakSlingRepositoryManager.java:144) [org.apache.sling.jcr.oak.server:1.2.0]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager.initializeAndRegisterRepositoryService(AbstractSlingRepositoryManager.java:481) [org.apache.sling.jcr.base:3.0.6]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager.access$300(AbstractSlingRepositoryManager.java:86) [org.apache.sling.jcr.base:3.0.6]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager$4.run(AbstractSlingRepositoryManager.java:462) [org.apache.sling.jcr.base:3.0.6]
Caused by: java.lang.RuntimeException: java.lang.InterruptedException
        at org.apache.felix.framework.ServiceRegistry.getService(ServiceRegistry.java:369)
        at org.apache.felix.framework.Felix.getService(Felix.java:3954)
        at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.transformClass(BundleWiringImpl.java:2383)
        at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.findClass(BundleWiringImpl.java:2081)
        at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1565)
        at org.apache.felix.framework.BundleWiringImpl.access$300(BundleWiringImpl.java:79)
        at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1982)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at org.apache.jackrabbit.oak.plugins.tree.factories.RootFactory.createSystemRoot(RootFactory.java:80) [org.apache.jackrabbit.oak-core:1.8.8]
        at org.apache.jackrabbit.oak.InitialContent.initialize(InitialContent.java:134) [org.apache.jackrabbit.oak-core:1.8.8]
        at org.apache.jackrabbit.oak.InitialContent.createInitialContent(InitialContent.java:74) [org.apache.jackrabbit.oak-core:1.8.8]
        at org.apache.jackrabbit.oak.InitialContent.<clinit>(InitialContent.java:70) [org.apache.jackrabbit.oak-core:1.8.8]
        ... 4 common frames omitted
Caused by: java.lang.InterruptedException: null
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1302)
        at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:231)
        at org.apache.felix.framework.ServiceRegistry.getService(ServiceRegistry.java:365)
        ... 15 common frames omitted

(source code for all classes is available if needed)

Starting the component C at any later time fails with

21.02.2019 14:50:50.310 *ERROR* [Apache Sling Repository Startup Thread #2] org.apache.sling.jcr.oak.server.internal.OakSlingRepositoryManager start: Uncaught Throwable trying to access Repository, calling stopRepository()
java.lang.NoClassDefFoundError: Could not initialize class org.apache.jackrabbit.oak.InitialContent
        at org.apache.sling.jcr.oak.server.internal.OakSlingRepositoryManager.acquireRepository(OakSlingRepositoryManager.java:144) [org.apache.sling.jcr.oak.server:1.2.0]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager.initializeAndRegisterRepositoryService(AbstractSlingRepositoryManager.java:481) [org.apache.sling.jcr.base:3.0.6]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager.access$300(AbstractSlingRepositoryManager.java:86) [org.apache.sling.jcr.base:3.0.6]
        at org.apache.sling.jcr.base.AbstractSlingRepositoryManager$4.run(AbstractSlingRepositoryManager.java:462) [org.apache.sling.jcr.base:3.0.6]