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Posted to log4j-dev@logging.apache.org by "Gary Gregory (JIRA)" <ji...@apache.org> on 2014/10/28 13:21:33 UTC

[jira] [Comment Edited] (LOG4J2-880) ConsoleAppender hangs when writing to System.out in a spawned JVM

    [ https://issues.apache.org/jira/browse/LOG4J2-880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14186748#comment-14186748 ] 

Gary Gregory edited comment on LOG4J2-880 at 10/28/14 12:21 PM:
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I take it you see the same behavior in Log4j 2.1?


was (Author: garydgregory):
I take you see the same behavior in Log4j 2.1?

> 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: Wish
>    Affects Versions: 2.0.2
>            Reporter: Daniel Widdis
>            Priority: Minor
>
> 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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