Bug 54325 - Concurrency issues in AppenderAttachableImpl
Summary: Concurrency issues in AppenderAttachableImpl
Status: NEW
Alias: None
Product: Log4j - Now in Jira
Classification: Unclassified
Component: Configurator (show other bugs)
Version: 1.2.17
Hardware: Other All
: P2 normal
Target Milestone: ---
Assignee: log4j-dev
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-12-19 07:49 UTC by Peter Jodeleit
Modified: 2012-12-19 12:51 UTC (History)
1 user (show)


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Description Peter Jodeleit 2012-12-19 07:49:38 UTC 
org.apache.log4j.helpers.AppenderAttachableImpl utilizes a java.util.Vector for internal storage, but at least in "removeAllAppenders()" additional synchronization is needed. We've got an integration test (part of a bigger setup) where we get reproducible an ArrayIndexOutOfBoundsException (see below).
Perhaps there is an issue with the test case (i.e. multiple calls to org.apache.log4j.PropertyConfigurator.configureAndWatch(..)) but this should be handled gracefully.

This is the exception we get:

java.lang.ArrayIndexOutOfBoundsException: 1 >= 1
at java.util.Vector.elementAt(Vector.java:470)
at org.apache.log4j.helpers.AppenderAttachableImpl.removeAllAppenders(AppenderAttachableImpl.java:139)
at org.apache.log4j.Category.removeAllAppenders(Category.java:868)
at org.apache.log4j.PropertyConfigurator.parseCategory(PropertyConfigurator.java:603)
at org.apache.log4j.PropertyConfigurator.configureRootCategory(PropertyConfigurator.java:509)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:415)
at org.apache.log4j.PropertyConfigurator.doConfigure(PropertyConfigurator.java:316)
at org.apache.log4j.PropertyWatchdog.doOnChange(PropertyConfigurator.java:682)
at org.apache.log4j.helpers.FileWatchdog.checkAndConfigure(FileWatchdog.java:88)
at org.apache.log4j.helpers.FileWatchdog.<init>(FileWatchdog.java:57)
at org.apache.log4j.PropertyWatchdog.<init>(PropertyConfigurator.java:674)
at org.apache.log4j.PropertyConfigurator.configureAndWatch(PropertyConfigurator.java:382)
at de.espirit.firstspirit.server.logging.LoggingManagerImpl.init(LoggingManagerImpl.java:118)
at de.espirit.firstspirit.server.AbstractManagerHost.addManager(AbstractManagerHost.java:99)
at de.espirit.firstspirit.server.MockManagerHost.getManager(MockManagerHost.java:177)
at de.espirit.firstspirit.server.MockManagerHost.getManager(MockManagerHost.java:166)
at de.espirit.firstspirit.server.ServerTestCase.getManager(ServerTestCase.java:251)
at de.espirit.firstspirit.server.ServerTestCase.setUp(ServerTestCase.java:175)
at de.espirit.firstspirit.io.servlet.TestRemoteLoggingDispatcher.setUp(TestRemoteLoggingDispatcher.java:48)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Comment 1 Jess Holle 2012-12-19 12:12:32 UTC 
This is one area where I've long since been patching log4j -- so that I can use a CopyOnWriteArrayList and avoid synchronization in this area, most especially on callAppenders().
Comment 2 Peter Jodeleit 2012-12-19 12:51:01 UTC 
I agree, using CopyOnWriteArrayList and iterator() would be the easiest fix. Is compatibility to JDK5 or lower still a prerequisite?