TEST_log4j.xml:3:22: The prefix "log4j" for element "log4j:configuration" is not bound

Question

I have to migrate from logj1.x to log4j2.x. For this, I have changed my below source code.

After I performed the below changes when I start the tomcat service I am getting the below error in the log file.

[Fatal Error] TEST_log4j.xml:3:22: The prefix "log4j" for element "log4j:configuration" is not bound.

Source Code changes From

import org.apache.log4j.Logger;
import org.apache.log4j.xml.DOMConfigurator;

To

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.config.Configurator;

From

private static Logger myLogger = Logger.getLogger(MyCustomClass.class);

To

private static Logger myLogger = LogManager.getLogger(MyCustomClass.class);

From

DOMConfigurator.configure("/home/user/TEST_log4j.xml");

To

Configurator.initialize(null, "/home/user/TEST_log4j.xml");

My /home/user/TEST_log4j.xml file configuration is given below

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration>
  <appender name="ConsoleAppender" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n"/>
    </layout>
  </appender>
  <appender name="Fileappender" class="org.apache.log4j.RollingFileAppender">
        <param name="file" value="/opt/tomcat/logs/MyCustomClassLogs.log"/>
        <param name="MaxFileSize" value="5MB"/>
        <param name="MaxBackupIndex" value="5"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n"/>
        </layout>
  </appender>
  <appender name="ResetClass" class="org.apache.log4j.RollingFileAppender">
            <param name="file" value="/opt/tomcat/logs/resetTrace.log"/>
            <param name="MaxFileSize" value="1MB"/>
            <param name="MaxBackupIndex" value="5"/>
            <layout class="org.apache.log4j.PatternLayout">
                <param name="ConversionPattern" value="%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n"/>
            </layout>
  </appender>
  <category name="com.demo.custom.filter.ResetClass" additivity="false">
        <priority value="TRACE"/>
        <appender-ref ref="ResetClass"/>
  </category>
  <category name="com.demo.custom.test.MyCustomClass" additivity="false">
        <priority value="TRACE"/>
        <appender-ref ref="Fileappender"/>
  </category>
  <root>
    <level value="error" />
    <appender-ref ref="ConsoleAppender"/>
  </root>
</log4j:configuration>

I am moving to log4j v 2.17.1.

Answer 1

I have resolved my issue by doing the below changes to my /home/user/TEST_log4j.xml

<Configuration>
    <Appenders>
        <Console name="STDOUT" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n"/>
        </Console>
        <RollingFile name="RollingFile" fileName="/opt/tomcat/logs/MyCustomClassLogs.log" filePattern="/opt/tomcat/logs/MyCustomClassLogs.log-%i">
            <PatternLayout>
                <pattern>%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n</pattern>
            </PatternLayout>
            <Policies>
                <SizeBasedTriggeringPolicy size="5 MB" />
            </Policies>
            <DefaultRolloverStrategy max="5"/>
        </RollingFile>
        <RollingFile name="ResetClass" fileName="/opt/tomcat/logs/resetTrace.log" filePattern="/opt/tomcat/logs/resetTrace.log-%i">
            <PatternLayout>
                <pattern>%d{MM/dd HH:mm:ss} %-5p %30.30c %x - %m\n</pattern>
            </PatternLayout>
            <Policies>
                <SizeBasedTriggeringPolicy size="5 MB" />
            </Policies>
            <DefaultRolloverStrategy max="5"/>
        </RollingFile>
    </Appenders>
    <Loggers>
        <Logger name="com.demo.custom.filter.ResetClass" level="TRACE">
            <AppenderRef ref="ResetClass"/>
        </Logger>
        <Logger name="com.demo.custom.test.MyCustomClass" level="TRACE">
            <AppenderRef ref="RollingFile"/>
        </Logger>
        <Root level="error">
            <AppenderRef ref="STDOUT"/>
        </Root>
    </Loggers>
</Configuration>