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Posted to notifications@logging.apache.org by "Constantin Hirsch (Jira)" <ji...@apache.org> on 2020/10/05 14:59:00 UTC
[jira] [Updated] (LOG4J2-2939) NPE in MDCContextMap

     [ https://issues.apache.org/jira/browse/LOG4J2-2939?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Constantin Hirsch updated LOG4J2-2939:
--------------------------------------
    Description: 
When using the SLF4J adapter and you call ThreadContext.containsKey() before putting anything into the ThreadContext, a NullPointerException is thrown:

{{ }}{{Exception in thread "main" +java.lang.NullPointerException+}}{{       at org.apache.logging.slf4j.MDCContextMap.containsKey(+MDCContextMap.java:74+)}}{{       at org.apache.logging.log4j.ThreadContext.containsKey(+ThreadContext.java:350+)}}{{       at de.semvox.logtest.LogtestApplication.main(+LogtestApplication.java:15+)}}

This is not surprising, as the implementation looks like this

{{@Override}}

{{*public* *boolean* containsKey(*final* String key) {}}

{{    *return* MDC._getCopyOfContextMap_().containsKey(key);}}{\{    }}}

 

And the Javadoc for getCopyOfContextMap explicitly states “May be null.”

This bug is also present in the isEmpty method of the same class.

 

Workaround: Before any tests are made, e.g. top of main, execute the following

{{ThreadContext.put(“foo”,”bar”);}}

{{ThreadContext.remove(“foo”);}}

 

I will create a pull request shortly.

UPDATE: Here is the pull request: [https://github.com/apache/logging-log4j2/pull/430]

  was:
When using the SLF4J adapter and you call ThreadContext.containsKey() before putting anything into the ThreadContext, a NullPointerException is thrown:

{{ }}{{Exception in thread "main" +java.lang.NullPointerException+}}{{       at org.apache.logging.slf4j.MDCContextMap.containsKey(+MDCContextMap.java:74+)}}{{       at org.apache.logging.log4j.ThreadContext.containsKey(+ThreadContext.java:350+)}}{{       at de.semvox.logtest.LogtestApplication.main(+LogtestApplication.java:15+)}}

This is not surprising, as the implementation looks like this

{{@Override}}

{{*public* *boolean* containsKey(*final* String key) {}}

{{    *return* MDC._getCopyOfContextMap_().containsKey(key);}}{{    }}}

 

And the Javadoc for getCopyOfContextMap explicitly states “May be null.”

This bug is also present in the isEmpty method of the same class.

 

Workaround: Before any tests are made, e.g. top of main, execute the following

{{ThreadContext.put(“foo”,”bar”);}}

{{ThreadContext.remove(“foo”);}}

 

I will create a pull request shortly.


> NPE in MDCContextMap
> --------------------
>
>                 Key: LOG4J2-2939
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-2939
>             Project: Log4j 2
>          Issue Type: Bug
>          Components: SLF4J Bridge
>    Affects Versions: 2.13.3
>         Environment: Empty fresh Spring Boot project on Windows 10 64Bit Oracle JDK11
>            Reporter: Constantin Hirsch
>            Priority: Major
>
> When using the SLF4J adapter and you call ThreadContext.containsKey() before putting anything into the ThreadContext, a NullPointerException is thrown:
> {{ }}{{Exception in thread "main" +java.lang.NullPointerException+}}{{       at org.apache.logging.slf4j.MDCContextMap.containsKey(+MDCContextMap.java:74+)}}{{       at org.apache.logging.log4j.ThreadContext.containsKey(+ThreadContext.java:350+)}}{{       at de.semvox.logtest.LogtestApplication.main(+LogtestApplication.java:15+)}}
> This is not surprising, as the implementation looks like this
> {{@Override}}
> {{*public* *boolean* containsKey(*final* String key) {}}
> {{    *return* MDC._getCopyOfContextMap_().containsKey(key);}}{\{    }}}
>  
> And the Javadoc for getCopyOfContextMap explicitly states “May be null.”
> This bug is also present in the isEmpty method of the same class.
>  
> Workaround: Before any tests are made, e.g. top of main, execute the following
> {{ThreadContext.put(“foo”,”bar”);}}
> {{ThreadContext.remove(“foo”);}}
>  
> I will create a pull request shortly.
> UPDATE: Here is the pull request: [https://github.com/apache/logging-log4j2/pull/430]



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