src/test/resources/input/xml/fallback1.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
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 contributor license agreements.  See the NOTICE file distributed with
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<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">


  <appender name="PRIMARY" class="org.apache.log4j.FileAppender">
    <errorHandler class="org.apache.log4j.varia.FallbackErrorHandler">
      <root-ref/>
      <appender-ref ref="FALLBACK" />
    </errorHandler>

    <!--
        The following path is carefully designed to fail on Linux and Windows,
        so that the appender FALLBACK is used instead and the test succeeds in
        the end. Linux considers "." as current directory, which can not be
        created as a file, while Windows strips "/."[1] internally and fails at
        ":", which is an invalid name.

        [1]: https://en.wikipedia.org/wiki/Filename#Comparison_of_filename_limitations
    -->
    <param name="File"      value="output/xyz/:/."   />
    <param name="Append"    value="false"            />

    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%-5p %c{2} - %m%n"/>
    </layout>
  </appender>

  <appender name="FALLBACK" class="org.apache.log4j.FileAppender">
    <param name="File" value="output/temp" />
    <param name="Append" value="false" />
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="FALLBACK - %c - %m%n"/>
    </layout>
  </appender>


  <root>
    <priority value ="debug" />
    <appender-ref ref="PRIMARY" />
  </root>

</log4j:configuration>