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How to set size and amount of log files (stdout, stderr) in tomcat?

I recently deployed a java app on my production server. In which I have installed Tomcat version 8.5 and I have been having problems since the log files stderr and stdout grow in size exaggeratedly and therefore I lower the performance of the server or sometimes it is necessary to restart it since it does not respond. I would like to know how to configure these files so that they create only a certain amount with a specific size. I have tried configuring it through log4j it has given me error when integrating this same a tomcat. I have also configured certain parameters (for example: java.util.logging.FileHandler.limit = 1024) for logging in which the size and quantity are assigned but these do not apply to the configuration and therefore I continue to throw the server .

In a production environment, a good practice is to use a process that works with small log files, and that creates a new one if the critical size has gone.
With log4j you can use a RollingFileAppender. See the minimal configuration :
<appender name="rolling.file.appender" class="org.apache.log4j.RollingFileAppender">
<param name="maxFileSize" value="50MB" />
<param name="maxBackupIndex" value="10" />
<param name="file" value="${catalina.base}/logs/myApplication.log" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p: %c - %m%n" />
</layout>
</appender>
<!-- Root Logger -->
<root>
<priority value="INFO" />
<appender-ref ref="rolling.file.appender" />
</root>
Documentation: https://tomcat.apache.org/tomcat-8.0-doc/logging.html

Confuguring log4j for multiple projects in the same app. server

We have a bunch of projects that get deployed in the same Jboss app. server. Each project has its own log4j.properties in its WEB-INF directory.
The idea is for each project to have its own logfile into which it writes its logs.
Any ideas on how this can be achieved.

First of all you don't mention the JBoss version you're using. You've to take in mind that JBoss versions prior to AS7 include its own log4j version (libraries and configuration file: conf/jboss-log4j.xml), so by default JBoss will ignore the log4j.properties file you've in each of your projects.
That said, you have two approaches to configure a log file for each application:
Centralized way: configure it in Jboss, through the
conf/jboss-log4j.xml. This way you won't need to modify your
applications, or
Modify your applications so that they take their own
log4j libraries (you'll have to include them in the ear/war), not
the Jboss ones.
For the first approach you'll have to define an appender for each of your applications, and then categories for the application packages, in the conf/jboss-log4j.xml file. For example, to configure a log file for an application called app1.war which classes are in a package called com.foo.app1, you'd have to add:
<appender name="APP1_APPENDER" class="org.jboss.logging.appender.DailyRollingFileAppender">
<errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
<param name="File" value="${jboss.server.log.dir}/app1.log"/>
<param name="Append" value="true"/>
<!-- Rollover at midnight each day -->
<param name="DatePattern" value="'.'yyyy-MM-dd"/>
<layout class="org.apache.log4j.PatternLayout">
<!-- The default pattern: Date Priority [Category] (Thread) Message\n -->
<param name="ConversionPattern" value="%d %-5p [%c] (%t) %m%n"/>
</layout>
</appender>
...
...
<category name="com.foo.app1" additivity="true">
<priority value="INFO"/>
<appender-ref ref="APP1_APPENDER"/>
</category>
You'll have to add a customized set of blocks like this one for each project you want to define a log file for, respectively.
If you prefer the second approach, as said you'll have to include the log4j libraries in each project and isolate each application so that it takes the libraries included in the application not the ones from JBoss. Look at section 10.3.7 of the Jboss logging file for more information about this approach.

JASIG CAS: How do I change where log files are written to?

I know very little about Java, let alone JASIG CAS.
We are trying to implement CAS on our CentOS 6 server. We are getting the following errors:
java.io.FileNotFoundException: cas.log (Permission denied)
[...snip...]
java.io.FileNotFoundException: perfStats.log (Permission denied)
After some investigation, it seems like tomcat6 is trying to write the log files in its home directory (/usr/share/tomcat6/). I was able to determine this by chown tomcat: /usr/share/tomcat6 and then, after a restart, the log files were created in that directory.
All the other logs though are written to /usr/share/tomcat6/logs which is a symlink to /var/log/tomcat6.
I want to know how do I reconfigure CAS to write these 2 log files to a different directory /usr/share/tomcat6/logs)?

Assuming you have a recent version of CAS, it uses log4j for logging, and you can find the log4j configuration in
$CATALINA_BASE/webapps/cas-server-webapp-VERSION/WEB-INF/classes/log4j.xml
For a standard Tomcat install under CentOS, $CATALINA_BASE would be /usr/share/tomcat.
If your log4j configuration has not been changed, you'll find an appender named "cas" near the top of the file which is responsible for creating cas.log. It looks like this:
<appender name="cas" class="org.apache.log4j.RollingFileAppender">
<param name="File" value="cas.log" />
<param name="MaxFileSize" value="512KB" />
<param name="MaxBackupIndex" value="3" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d %p [%c] - %m%n"/>
</layout>
</appender>
Further down you'll find another appender named "fileAppender", which creates the perfStats.log file.
<appender name="fileAppender" class="org.apache.log4j.FileAppender">
<param name="File" value="perfStats.log"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%m%n"/>
</layout>
</appender>
See how the value for the File parameters is just a file name with no directory specified? The log files therefore get created in the $CATALINA_BASE directory. To get them into the Tomcat logs directory where you want them, just change the values to logs/cas.log and logs/perfStats.log.
Note that CAS only reads the log4j config at startup, so once you've made the change you'll have to either undeploy and redeploy CAS or bounce Tomcat for it to take effect.

What is the best way to use log4j in the web application?

We are starting a Spring MVC based web application. We will be using tomcat as the web server.
I need to configure log4j in the application and log to the application specific file and not to the tomcat log files.
e.g. tomcat has its own log files like localhost.log etc. I want something like myAppName.log in the tomcats log folder.
The logging configuration will go in lo4j.xml or log4j.properties in the application war file.
Plus I dont want to hard code the output log file in the web application.
But I am not sure how to do this.
Please help me. As well correct me if I am wrong somewhere.

Do like this, initialize the logger with following code,
Logger log = Logger.getLogger(this.getClass());
log the information like follows,
log.debug("My message");
and place the log4j.xml in your class path. content like follows,
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="infoLogsFile" class="org.apache.log4j.RollingFileAppender">
<param name="File" value="MyApplication.log"/>
<param name="Threshold" value="DEBUG"/>
<param name="MaxFileSize" value="100MB"/>
<param name="ImmediateFlush" value="TRUE"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d %-5p [%c] %m%n"/>
</layout>
</appender>
<root>
<priority value ="DEBUG" />
<appender-ref ref="infoLogsFile"/>
</root>
</log4j:configuration>
Do not forget to add the required jars like log4jXXX.jars and apache common logging jars. with this you will be able to see all log messages in MyApplication.log file creates in bin folder of your tomcat.

Try this:
Put the log4j jar as part of the web application
Do not put a configuration as part of your web application
Create your log4j.xml wherever you like
When you start tomcat provide this argument
-Dlog4j.configuration=file:///.../log4j.xml

Creating multiple log files of different content with log4j

Is there a way to configure log4j so that it outputs different levels of logging to different appenders?
I'm trying to set up multiple log files. The main log file would catch all INFO and above messages for all classes. (In development, it would catch all DEBUG and above messages, and TRACE for specific classes.)
Then, I would like to have a separate log file. That log file would catch all DEBUG messages for a specific subset of classes, and ignore all messages for any other class.
Is there a way to get what I'm after?

This should get you started:
log4j.rootLogger=QuietAppender, LoudAppender, TRACE
# setup A1
log4j.appender.QuietAppender=org.apache.log4j.RollingFileAppender
log4j.appender.QuietAppender.Threshold=INFO
log4j.appender.QuietAppender.File=quiet.log
...
# setup A2
log4j.appender.LoudAppender=org.apache.log4j.RollingFileAppender
log4j.appender.LoudAppender.Threshold=DEBUG
log4j.appender.LoudAppender.File=loud.log
...
log4j.logger.com.yourpackage.yourclazz=TRACE

Perhaps something like this?
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<!-- general application log -->
<appender name="MainLogFile" class="org.apache.log4j.FileAppender">
<param name="File" value="server.log" />
<param name="Threshold" value="INFO" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %t [%-40.40c] %x - %m%n"/>
</layout>
</appender>
<!-- additional fooSystem logging -->
<appender name="FooLogFile" class="org.apache.log4j.FileAppender">
<param name="File" value="foo.log" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %t [%-40.40c] %x - %m%n"/>
</layout>
</appender>
<!-- foo logging -->
<logger name="com.example.foo">
<level value="DEBUG"/>
<appender-ref ref="FooLogFile"/>
</logger>
<!-- default logging -->
<root>
<level value="INFO"/>
<appender-ref ref="MainLogFile"/>
</root>
</log4j:configuration>
Thus, all info messages are written to server.log; by contrast, foo.log contains only com.example.foo messages, including debug-level messages.

I had this question, but with a twist - I was trying to log different content to different files. I had information for a LowLevel debug log, and a HighLevel user log. I wanted the LowLevel to go to only one file, and the HighLevel to go to both a file, and a syslogd.
My solution was to configure the 3 appenders, and then setup the logging like this:
log4j.threshold=ALL
log4j.rootLogger=,LowLogger
log4j.logger.HighLevel=ALL,Syslog,HighLogger
log4j.additivity.HighLevel=false
The part that was difficult for me to figure out was that the 'log4j.logger' could have multiple appenders listed. I was trying to do it one line at a time.
Hope this helps someone at some point!

For the main logfile/appender, set up a .Threshold = INFO to limit what is actually logged in the appender to INFO and above, regardless of whether or not the loggers have DEBUG, TRACE, etc, enabled.
As for catching DEBUG and nothing above that... you'd probably have to write a custom appender.
However I'd recommend not doing this, as it sounds like it would make troubleshooting and analysis pretty hard:
If your goal is to have a single file where you can look to troubleshoot something, then spanning your log data across different files will be annoying - unless you have a very regimented logging policy, you'll likely need content from both DEBUG and INFO to be able to trace execution of the problematic code effectively.
By still logging all of your debug messages, you are losing any performance gains you usually get in a production system by turning the logging (way) down.

Demo link: https://github.com/RazvanSebastian/spring_multiple_log_files_demo.git
My solution is based on XML configuration using spring-boot-starter-log4j. The example is a basic example using spring-boot-starter and the two Loggers writes into different log files.