log4j:WARN No such property [append] while creating a custom Appender

Question

Can anyone suggest how to get rid of this error.

I have made a custom Appender with the help of How to create a own Appender in log4j?

My appender is:

package com.abc.log4jlearn;

import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;

public class MyAppender extends AppenderSkeleton{
    private LogManager logManager;

    public MyAppender (){
        this.logManager = LogManager.getInstance();
    }

    @Override
    protected void append(LoggingEvent loggingEvent) {
        String message = loggingEvent.getMessage().toString();
        logManager.addthese(message);
    }

    @Override
    public void close() {
        if(this.closed) {
            return;
        }
        this.closed = true;
    }
    @Override
    public boolean requiresLayout() {
        return false;
    }

    boolean checkEntryConditions() {
        return true;
    }
}

LogManager class is:

public class LogManager {
    public LogManager() {}

    public static LogManager getInstance() {
        return new LogManager();

    }
    public void addthese(String message) {
        System.out.println("Hey...");
        System.out.println(message);

    }
}

Log4j.xml configuration is :

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
    <appender name="MyAppender" class="package com.abc.log4jlearn.MyAppender">
        <param name="Append" value="false"/>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%-5p %d{ISO8601} %c{1} - %m%n"/>
        </layout>
    </appender>

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

</log4j:configuration>

Test Class is:

public class Log4jLearnkDemo {
private static Logger logger = Logger.getLogger(Log4jLearnkDemo.class);
public static void main(String[] args){
    logger.debug("Hello this is a debug message");
    logger.info("Hello this is an info message");

}
}

When I run Log4jLearnDemo class I am getting output

Hey...
Hello this is a debug message
Hey..
Hello this is an info message
log4j:WARN No such property [append] in com.abc.log4jlearn.MyAppender.

Can somebody suggest why I am getting this error ?

Thanks,

score 4 · Accepted Answer · answered May 04 '15 at 15:17

4

In your Log4j.xml you define the following line for a param named "Append" with value "false":

 <param name="Append" value="false"/>

If you uncomment this (maybe it is from the example you took)

<!-- param name="Append" value="false"/ -->

the message will disappear.

Otherwise, if you want to give MyAppender an "append"-Logic, the class might need something like

private boolean append;
// get/set for the property

answered May 04 '15 at 15:17

swinkler

1,703
10
20

Thanks .. by uncommenting I got rid of this error :) , but I didn't understand logic behind this. Can you throw some light on this ? – Geek_To_Learn May 04 '15 at 15:20
The param tag tells Log4j that your class MyAppender has a property called "append" which should be initialized with "false" - so when your appender is loaded Log4j tries to pass the "false" value into your class. But cannot find any property "append". – swinkler May 04 '15 at 15:26

log4j:WARN No such property [append] while creating a custom Appender

1 Answers1