How to make 2 or more java project write in a single log file

Question

I am using log4j to write all the logs in a file. i have 2 different java projects say proj1 and proj2, where project1 is required project for proj2. I have added proj1 as a dependency for proj2.

proj1 has log4j setup done and is working fine.
Now my problem is when I am running a method in proj2, it will call proj1 as well.
So I want to have a single logfile for both the projects.

Any input please?

score 1 · Answer 1 · edited May 23 '17 at 10:32

1

There are several ways to write to a single log file but which way is best depends on a couple of details which you omit.

If proj2 includes proj1 as a library, you can make it use proj1's log4j configuration file. This works because you only have a single VM. The most simple solution here is to either copy the first project's config into the other or not give the second project any log config; it will then read the config from its dependencies.

If proj2 starts proj1 as an external process, you need to configure both projects to use a SocketAppender since only a single Java VM can ever write to a single log file.

log4j: How to use SocketAppender?

edited May 23 '17 at 10:32

Community

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1

answered Aug 29 '13 at 11:38

Aaron Digulla

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Thanks Aaron. I have made it working. Here is what i have done.I just copied proj1's log4j.properties file to proj2 and then i had single log for any execution between proj1 and proj2. – Pratik Aug 29 '13 at 12:00
you may use root logger configuration for external appender.there will be no need of raplacing or copying log4j.xml. – Amit Singh Aug 29 '13 at 13:45

score 0 · Answer 2 · answered Aug 29 '13 at 13:42

I was also facing the same problem but i got the solution and have configured my log4j.xml like this:

used a appender:

<appender name="FILE1" class="org.apache.log4j.RollingFileAppender">
        <errorHandler class="org.apache.log4j.helpers.OnlyOnceErrorHandler" />
        <param name="File" value="E:/OESController.log" />
        <param name="Append" value="true" />
        <param name="MaxFileSize" value="20KB" />
        <param name="MaxBackupIndex" value="2" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%-5p: %d{dd MMM yyyy HH:mm:ss.SSS} %-5l - %m%n%n" />
        </layout>
    </appender>


<!-- Root Logger -->
    <root>
        <priority value="error" />
            <appender-ref ref="FILE" />     
    </root>

Note:*Root logger logs for entire application.*

let me know if you still face the problem.

How to make 2 or more java project write in a single log file

2 Answers2