Develop Reference

How can I specify a specific format for each Log4j log level

First time trying to use log4j version log4j-1.2.17.jar.
On an existing application the client has log4j in place and there is a log4j.properties file which specifies a light log output. What I want to do is depending on the log level (ERROR & WARN) output a more refined entry.
On the log4j site I came across this but I think it is to be in some .xml file. I need some assistance in understanding how I can put in place the formatting option to alter based on log level.
You don't need to declare separate loggers to achieve this. You can set the logging level on the AppenderRef element.
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<File name="file" fileName="app.log">
<PatternLayout>
<Pattern>%d %p %c{1.} [%t] %m %ex%n</Pattern>
</PatternLayout>
</File>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%m%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="trace">
<AppenderRef ref="file" level="DEBUG"/>
<AppenderRef ref="STDOUT" level="INFO"/>
</Root>
</Loggers>
</Configuration>
Would I put this xml content into the web.xml file or another file?
a) If another file what file name and where would it go?
How do I get log4j to realize that I need it to use the xml file?
Will the use of the xml ignore the log4j.properties file?
I know it is a lot of questions but there is only me on the project and the client has a production crisis that needs to be figured out today so I don't have time to go off to read and do tutorials with the client calling me every hour. I figured it may help to get this logging more useful. As the logs are right now I have a date and message output to the log but no idea where the entries are created from without doing extensive searches through the code.

You could do this by defining multiple non-additive Loggers so that the first one only logs errors, the next one warnings and the final one infos and debug.

Log4j 2 - Deactivate drools logger

I am using Log4j 2 and I am unsuccessfully trying to change the logging level of jBPM/Drools, having it as a reference. The drools class that keeps logging is ExtensibleXmlParser.
<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</Console>
</Appenders>
<Loggers>
<Root level="debug">
<AppenderRef ref="Console" />
</Root>
<Logger name="org.drools.core.xml.ExtensibleXmlParser" level="off">
<AppenderRef ref="Console" />
</Logger>
</Loggers>
</Configuration>
If I get it right, ExtensibleXmlParser uses slf4j and Log4j is compatible with sl4j.
Why doesn't this Log4j configuration work? Could someone provide me a working configuration? Should I configure jBPM/Drools logger indendently?

When log4j seems to ignore your tweaks to the log4j.properties/xml file, it most often means you're not fiddling with the right file. It is likely that there is another configuration file in your classpath that gets found earlier and is taken into account.
Search your entire classpath for log4j* pattern and see what comes out (include the contents of .jar files and application server /lib and /ext folders, if any).
If I get it right, ExtensibleXmlParser uses slf4j and Log4j is compatible with sl4j.
"Is compatible" is not equivalent with "is configured to use". SLF4J plugs into appropriate logging framework through the org.slf4j.impl.StaticLoggerBinder class. Search the classpath (best in your IDE) to see what library this class came with. If there is no such class, then SLF4J logs nothing.

System.out.println not printing to console

I have a Spring web app running on Wildfly 8.* and for some reason it won't print to the console. I see all the console logs and stack traces fine but the System messages just don't appear.
The problem might be with my log4j setup so I'll post that config;
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration PUBLIC
"-//APACHE//DTD LOG4J 1.2//EN" "http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/xml/doc-files/log4j.dtd">
<log4j:configuration debug="true"
xmlns:log4j='http://jakarta.apache.org/log4j/'>
<appender name="console" class="org.apache.log4j.ConsoleAppender">
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern"
value="%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n" />
</layout>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="console" />
</root>
</log4j:configuration>
I've ran apps on JBoss 7.1 before however without this problem so I'm really at a loss on what could be wrong.
Feel free to ask about any of my other config not sure what would be needed.
Edit:
logger.org.jboss.as.config.level=DEBUG
logger.org.jboss.as.config.useParentHandlers=true
logger.jacorb.config.level=ERROR
logger.jacorb.config.useParentHandlers=true
logger.org.apache.tomcat.util.modeler.level=WARN
logger.org.apache.tomcat.util.modeler.useParentHandlers=true
logger.com.arjuna.level=WARN
logger.com.arjuna.useParentHandlers=true
handler.CONSOLE=org.jboss.logmanager.handlers.ConsoleHandler
handler.CONSOLE.level=INFO
handler.CONSOLE.formatter=COLOR-PATTERN
handler.CONSOLE.properties=autoFlush,target,enabled
handler.CONSOLE.autoFlush=true
handler.CONSOLE.target=SYSTEM_OUT
handler.CONSOLE.enabled=true
handler.FILE=org.jboss.logmanager.handlers.PeriodicRotatingFileHandler
handler.FILE.level=ALL
handler.FILE.formatter=PATTERN
handler.FILE.properties=append,autoFlush,enabled,suffix,fileName
handler.FILE.constructorProperties=fileName,append
handler.FILE.append=true
handler.FILE.autoFlush=true
handler.FILE.enabled=true
handler.FILE.suffix=.yyyy-MM-dd
handler.FILE.fileName=C\:\\wildfly-8.2.0.Final\\standalone\\log\\server.log
formatter.PATTERN=org.jboss.logmanager.formatters.PatternFormatter
formatter.PATTERN.properties=pattern
formatter.PATTERN.pattern=%d{yyyy-MM-dd HH\:mm\:ss,SSS} %-5p [%c] (%t) %s%E%n
formatter.COLOR-PATTERN=org.jboss.logmanager.formatters.PatternFormatter
formatter.COLOR-PATTERN.properties=pattern
formatter.COLOR-PATTERN.pattern=%K{level}%d{HH\:mm\:ss,SSS} %-5p [%c] (%t) %s%E%n
Here is my logging config in my standalone deployments folder.

I had a log4j.properties file at the root level of the .war (WEB-INF/classes) from years ago that caused the same issue - deletion fixed it

Since you are using a logging framework, there are 2 ways to fix it:
Remove the logging framework and all the configuration files (why would I do that)
Move your log4j.properties file from src/main/resources to WEB-INF folder.
Quoting: JBoss Docs, Section 'Per Deployment Logging'
Per-deployment logging allows you to add a logging configuration file to your deployment and have the logging for that deployment configured according to the configuration file. In an EAR the configuration should be in the META-INF directory. In a WAR or JAR deployment the configuration file can be in either the META-INF or WEB-INF/classes directories.
The following configuration files are allowed:
logging.properties
jboss-logging.properties
log4j.properties
log4j.xml
jboss-log4j.xml

I usually have trouble configuring logs per deployment in wildfly, but you can use the logging system from wildfly, changing logging configuration of your standalone ou domain config files to this would do the trick:
<root-logger>
<level name="TRACE"/>
<handlers>
<handler name="CONSOLE"/>
<handler name="FILE"/>
</handlers>
</root-logger>

Log4j2 Servlet 3.0 not logging

I have a JAX-RS 2.0 application running on a Tomcat 7 server, and I'm using log4j2 along with SLF4J to record the server logs to a file.
I can't seem to get any logs to show up properly in my log file when running the server in production, although when I run my integration tests, logs are output correctly.
In production, the logs are merely redirected to the console instead.
My log4j2.xml file is located in the WEB-INF/classes folder, and I've included all the necessary dependencies as well.
My configuration file looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="trace">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
<RollingFile name="file" fileName="log/trace.log" append="true" filePattern="log/trace.%i.log">
<PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %X %logger{36} - %msg%n"/>
<Policies>
<OnStartupTriggeringPolicy/>
<SizeBasedTriggeringPolicy size="10 MB" />
</Policies>
</RollingFile>
</Appenders>
<Loggers>
<Logger name="my.package" level="TRACE" additivity="false">
<AppenderRef ref="file"/>
</Logger>
<Root level="WARN">
<AppenderRef ref="file"/>
</Root>
</Loggers>
</Configuration>
The web.xml needs no configuration (I'm following the documentation found on the log4j2 website).
EDIT
I've tried setting the Root level to TRACE but everything still gets redirected to console. The file log/trace.log itself is created, it's just never written to. I also tried setting immediateFlush=true but that didn't have any impact either.

I noticed you have status logging (log4j internal logging) set to TRACE. This will dump log4j internal initialization messages to the console. It this what you mean?
Otherwise, the config you provide shows there is no logger that has an appender-ref pointing to the ConsoleAppender.
So, if you are also seeing your application logs being output to the console (in addition to log4j's status log messages), I suspect there is another log4j2.xml (or log4j2-test.xml) config file in the classpath somewhere.
Fortunately log4j's status logs should also show the location of the log4j config file, so you can confirm which config file is actually being loaded.
You can switch off status logging by setting <Configuration status="WARN"> after confirming all works correctly.

I figured it out!
Turns out I was using the gretty plug-in with gradle, which contains it's own logging package (the logback library).
It used it's own internal logback.xml which was redirecting to console. I fixed this by overwriting the internal logback.xml with my own (using logback's configuration) and now everything works as expected!

Silencing Flyway -- a log4j problem

I've written a wrapper around Flyway I call Nomad. I am well pleased with Flyway, save the incessant logging it performs outside of Maven. I created an issue here. Each user of Nomad must make their own configuration of log4j to silence Flyway. This is problematic if not done, for instance, during Spec testing. However, getting the configuration just right is a challenge and, moreover, having to do this breaks the abstraction of my library.
My question is this: how can I permanently silence flyway so that any user of Nomad is not burdened with the task? I've found that this log4j.xml sometimes works:
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="console" class="org.apache.log4j.ConsoleAppender">
<param name="Target" value="System.out"/>
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%d{ISO8601} %t %-5p %c{1} - %m%n"/>
</layout>
</appender>
<logger name="org.springframework" additivity="false">
<level value="error"/>
<appender-ref ref="console"/>
</logger>
<root>
<priority value="error"/>
<appender-ref ref="console"/>
</root>
</log4j:configuration>
This stifles Flyway to the point of being helpful, rather than overly chatty. The misdirection is still broken, but not often.

The way you have done it in log4j.xml seems good. I don't see anything wrong.
Since the project uses Maven, I recommend you adding a property file instead log4j.properties, that you place that in src/main/resources
The contents can be:
log4j.rootCategory=DEBUG, stderr
log4j.appender.stderr=org.apache.log4j.ConsoleAppender
log4j.appender.stderr.target=System.err
log4j.appender.stderr.layout=org.apache.log4j.PatternLayout
log4j.appender.stderr.layout.ConversionPattern=[%d] %-5p %c %x: %m%n
# Silence springframework messages.
org.springframework=ERROR
Perhaps that will work better with you. It becomes easier to manage too.

Flyway's only non-logging framework dependency is Spring. As Mohamed Mansour pointed out you can suppress all but the ERROR messages with a simple Log4J configuration setting.
For Spring (as pointed out by Mohamed Mansour):
org.springframework=ERROR
For Flyway:
com.googlecode.flyway=ERROR