[QPID-3311] ConcurrentModificationException in java client during failover

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Later
• Fix Version/s: JIRA Cleanup
• Component/s: JMS AMQP 0-x
• Assignee: Unassigned
• Reporter: Siddhesh Poyarekar
• Created: 20/Jun/11 05:17
• Updated: 05/Sep/11 21:46
• Resolved: 05/Sep/11 21:46

Description

Description of problem:
The java client removes transacted sessions during failover. This removal is
not safe however, since it happens when the Hashmap of sessions is being
iterated through. This occasionally results in a
ConcurrentModificationException.

How reproducible:
Always

Steps to Reproduce:
1. Run attached program

Actual results:

ERROR [IoReceiver - localhost/127.0.0.1:5672]
(AMQConnectionDelegate_0_10.java:281) - error during failover
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:810)
at java.util.HashMap$ValueIterator.next(HashMap.java:839)
at org.apache.qpid.transport.Connection.resume(Connection.java:469)
at
org.apache.qpid.client.AMQConnectionDelegate_0_10.resubscribeSessions(AMQConnectionDelegate_0_10.java:221)
at
org.apache.qpid.client.AMQConnection.resubscribeSessions(AMQConnection.java:1207)
at
org.apache.qpid.client.AMQConnectionDelegate_0_10.closed(AMQConnectionDelegate_0_10.java:274)
at org.apache.qpid.transport.Connection.closed(Connection.java:561)
at org.apache.qpid.transport.network.Assembler.closed(Assembler.java:110)
at
org.apache.qpid.transport.network.InputHandler.closed(InputHandler.java:202)
at org.apache.qpid.transport.network.io.IoReceiver.run(IoReceiver.java:150)
at java.lang.Thread.run(Thread.java:636)
ERROR [IoReceiver - localhost/127.0.0.1:5672]
(AMQConnectionDelegate_0_10.java:293) - connection exception: conn:3749eb9f
org.apache.qpid.transport.ConnectionException: connection aborted
at org.apache.qpid.transport.Connection.closed(Connection.java:534)
at org.apache.qpid.transport.network.Assembler.closed(Assembler.java:110)
at
org.apache.qpid.transport.network.InputHandler.closed(InputHandler.java:202)
at org.apache.qpid.transport.network.io.IoReceiver.run(IoReceiver.java:150)
at java.lang.Thread.run(Thread.java:636)

Expected results:
Successful failover

Additional info:

Logging options (log4j.properties):

log4j.rootLogger=debug, stdout, R

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

1. Pattern to output the caller's file name and line number.
   log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n

log4j.appender.R=org.apache.log4j.FileAppender
log4j.appender.R.File=example.log

log4j.appender.R.MaxFileSize=100000000KB

1. Keep one backup file
   log4j.appender.R.MaxBackupIndex=1

log4j.appender.R.layout=org.apache.log4j.PatternLayout

log4j.logger.org.apache=TRACE