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Catch stderr and stdout in log4j before unix redirection

I use log4j in my application to log specific packages with a different log level.

However, stderr and stdout are not displayed in this log file, and instead they are printed in the file when the application starts with

java AppName >> out.log

Is it possible to catch stdout and stderr in log4j (for example, stdout as information and stderr as WARN / ERROR) and in the out.log file?

The settings for log4j are as follows:

 <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/"> <appender name="FileAppender" class="org.apache.log4j.DailyRollingFileAppender"> <param name="File" value="${MDCapture.logfile.dir}/${APP_NAME}.log"/> <param name="BufferedIO" value="false"/> <param name="DatePattern" value="'.'yyyy-MMM-dd"/> <layout class="org.apache.log4j.TTCCLayout"> <param name="DateFormat" value="ISO8601"/> </layout> </appender> <appender name="AsyncAppenders" class="org.apache.log4j.AsyncAppender"> <appender-ref ref="FileAppender"/> </appender> <!-- LOGGER PACKAGES --> <root> <priority value="info"/> <appender-ref ref="AsyncAppenders"/> </root> </log4j:configuration>

UPDATE:

Stacktrace for stackoverflow error:

 WARN root buffer size limit:65log4j:WARN root buffer size limit:65Exception in thread "Thread-12" 2013-03-22 09:14:24,451 [Thread-12] ERROR root - java.lang.StackOverflowError 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at java.io.BufferedWriter.write(BufferedWriter.java:202) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at java.io.Writer.write(Writer.java:140) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at java.io.PrintStream.write(PrintStream.java:475) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at java.io.PrintStream.print(PrintStream.java:619) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at java.io.PrintStream.println(PrintStream.java:756) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.helpers.LogLog.warn(LogLog.java:171) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.AsyncAppender.append(AsyncAppender.java:175) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.Category.callAppenders(Category.java:206) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.Category.forcedLog(Category.java:391) 2013-03-22 09:14:24,452 [Thread-12] ERROR root - at org.apache.log4j.Category.log(Category.java:838) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at com.company.something.AClass.LoggingOutputStream.flush(LoggingOutputStream.java:198) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at java.io.PrintStream.write(PrintStream.java:432) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:202) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:272) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at sun.nio.cs.StreamEncoder.flushBuffer(StreamEncoder.java:85) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at java.io.OutputStreamWriter.flushBuffer(OutputStreamWriter.java:168) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at java.io.PrintStream.write(PrintStream.java:477) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at java.io.PrintStream.print(PrintStream.java:619) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at java.io.PrintStream.println(PrintStream.java:756) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at org.apache.log4j.helpers.LogLog.warn(LogLog.java:171) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at org.apache.log4j.AsyncAppender.append(AsyncAppender.java:175) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251) 2013-03-22 09:14:24,453 [Thread-12] ERROR root - at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:
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2 answers

To redirect stdout and stderr to log4j, try something like this:

 System.setErr( new PrintStream( new LoggingOutputStream( Logger.getRootLogger( ), Level.ERROR ), true); System.setOut( new PrintStream( new LoggingOutputStream( Logger.getRootLogger( ), Level.INFO ), true);

For LoggingOutputStream you can start with in this example

To make log4j print what you want to use in the console (and write it back to the / node file if you want), enable ConsoleAppender to the right level

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For log4j 2.x:

 System.setErr(IoBuilder.forLogger(LogManager.getRootLogger()).setLevel(Level.ERROR).buildPrintStream()); System.setOut(IoBuilder.forLogger(LogManager.getRootLogger()).setLevel(Level.INFO).buildPrintStream());

Addiction Information:

  • group: org.apache.logging.log4j
  • artifact: log4j-iostreams
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