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https://issues.apache.org/jira/browse/LOG4J2-880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14181466#comment-14181466
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Daniel Widdis commented on LOG4J2-880:
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I'll do my best.... patch should be easy. Figuring out the condition to test on
notsomuch...
> ConsoleAppender hangs when writing to System.out in a spawned JVM
> -----------------------------------------------------------------
>
> Key: LOG4J2-880
> URL: https://issues.apache.org/jira/browse/LOG4J2-880
> Project: Log4j 2
> Issue Type: Bug
> Affects Versions: 2.0.2
> Reporter: Daniel Widdis
>
> I am using Log4J2 in an application using Java Parallel Processing Framework
> (www.jppf.org). One of the features of JPPF is node provisioning, in which a
> node process can spawn additional JVMs. However, since the spawned JVMs do
> not have a "console" the only way to access System.out is by redirecting it
> to a file, which is done automatically.
> By default, the ConsoleAppender sets {{follow="false"}}. However, rather
> than exiting gracefully doing nothing, it locks an OutputStreamManger and
> never releases it. This causes the application to hang.
> The problem is easily worked around by setting {{follow="true"}} on the
> appender. However, I propose that the default behavior for {{follow="false"}}
> when System.out is unavailable (as in a spawned JVM) should simply return
> without doing anything, rather than locking resources.
> Relevant stack trace of the thread holding the lock is shown below. The
> {{writeBytes()}} method never returned. Other threads attempted to write but
> were blocked because of this lock.
> "pool-5-thread-6" prio=6 tid=0x000000000c0c2000 nid=0x2ce4 runnable
> [0x000000000d9ae000]
> java.lang.Thread.State: RUNNABLE
> at java.io.FileOutputStream.writeBytes(Native Method)
> at java.io.FileOutputStream.write(Unknown Source)
> at java.io.BufferedOutputStream.write(Unknown Source)
> - locked <0x00000000d0063960> (a java.io.BufferedOutputStream)
> at java.io.PrintStream.write(Unknown Source)
> - locked <0x00000000d0063940> (a java.io.PrintStream)
> at
> org.apache.logging.log4j.core.appender.OutputStreamManager.write(OutputStreamManager.java:122)
> - locked <0x00000000d00638e0> (a
> org.apache.logging.log4j.core.appender.OutputStreamManager)
> at
> org.apache.logging.log4j.core.appender.OutputStreamManager.write(OutputStreamManager.java:136)
> at
> org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.append(AbstractOutputStreamAppender.java:106)
> at
> org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:97)
> at
> org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:428)
> at
> org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:407)
> at
> org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:410)
> at
> org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:365)
> at org.apache.logging.log4j.core.Logger.logMessage(Logger.java:112)
> at
> org.apache.logging.log4j.spi.AbstractLogger.logMessage(AbstractLogger.java:1336)
> at
> org.apache.logging.log4j.spi.AbstractLogger.logIfEnabled(AbstractLogger.java:1325)
> at
> org.apache.logging.log4j.spi.AbstractLogger.warn(AbstractLogger.java:1738)
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