ConcurrentModificationException when using MDC ---------------------------------------------- Key: LBCLASSIC-289 URL: http://jira.qos.ch/browse/LBCLASSIC-289 Project: logback-classic Issue Type: Bug Components: appender Affects Versions: 0.9.29 Environment: Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02-383, mixed mode) Darwin aden 11.1.0 Darwin Kernel Version 11.1.0: Tue Jul 26 16:07:11 PDT 2011; root:xnu-1699.22.81~1/RELEASE_X86_64 x86_64 Reporter: Josh Oddman Assignee: Logback dev list In some rare cases in multithreaded environment MDC.put throws ConcurrentModificationException. java.util.ConcurrentModificationException: null at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793) ~[na:1.6.0_26] at java.util.HashMap$EntryIterator.next(HashMap.java:834) ~[na:1.6.0_26] at java.util.HashMap$EntryIterator.next(HashMap.java:832) ~[na:1.6.0_26] at java.util.HashMap.putAll(HashMap.java:523) ~[na:1.6.0_26] at ch.qos.logback.classic.util.LogbackMDCAdapter.duplicateAndInsertNewMap(LogbackMDCAdapter.java:69) ~[logback-classic-0.9.29.jar:na] at ch.qos.logback.classic.util.LogbackMDCAdapter.put(LogbackMDCAdapter.java:95) ~[logback-classic-0.9.29.jar:na] at org.slf4j.MDC.put(MDC.java:112) ~[slf4j-api-1.6.1.jar:1.6.1] -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://jira.qos.ch/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira