[LOG4J2-176] IllegalArgumentException during AsyncAppender shutdown

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0-beta4
• Fix Version/s: 2.0-beta5
• Component/s: Core

Environment

Windows 2000, JDK1.6.0_031, single-cpu machine, multiple threads calling Logger.log

• Assignee: Ralph Goers
• Reporter: Remko Popma
• Created: 15/Mar/13 10:20
• Updated: 01/Apr/13 05:46
• Resolved: 26/Mar/13 06:15

Description

I am seeing the following exception:
Exception in thread "Thread-7" java.lang.IllegalArgumentException: Event is not a serialized LogEvent: Shutdown
at org.apache.logging.log4j.core.impl.Log4jLogEvent.deserialize(Log4jLogEvent.java:303)
at org.apache.logging.log4j.core.appender.AsynchAppender$AsynchThread.run(AsynchAppender.java:229)

(I cannot reproduce this on other platforms)

I think this is what is happening:
[AppThread] calls ((LifeCycle) LogManager.getContext()).stop();
[AppThread] sets AsyncAppender.shutdown field to true (line 240)
[AsyncThread] breaks out of while(!shutdown) loop (line 196)
[AppThread] adds String "Shutdown" to queue
[AsyncThread] processes remaining items in the queue, tries to deserialize String "Shutdown" -> Error

Solution:
replace AsyncAppender line 229:
final Log4jLogEvent event = Log4jLogEvent.deserialize(queue.take());
with
Serializable s = queue.take();
if (SHUTDOWN.equals(s))

{ continue; }

// or break?
final Log4jLogEvent event = Log4jLogEvent.deserialize(s);
....

I don't think this is a major issue as the AsyncThread will exit its run() method (so JVM can exit), it just looks a bit sloppy.