Develop Reference

log4j property change not getting reflected in Eclipse

This was the log4j file I used for my project till I checked in my project to a SVN repository. This was working fine and I saw log information on Eclipse's console
log4j.rootLogger=debug, stdout, R
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%d - %p %t %C.%M (%F:%L) %m%n
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=x.log
log4j.appender.R.MaxFileSize=100KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%d - %p %t %C.%M (%F:%L) %m%n
I checked out my project from repository and disabled logging by making this change in my log4j property file.
#log4j.rootLogger=debug, stdout, R
log4j.rootLogger=OFF
But this change didn't work as expected, I still got the log information on Eclipse's console. When I cross checked the same on Terminal, it was fine, I didn't get log info on Terminal. Any problem with Eclipse? I searched a lot on this issue, didn't get any solution. Help me in finding out what's wrong here!!!

There are two possible issues here:
the configuration should say (to tell it no appenders, instead of looking for OFF appender):
log4j.rootLogger=
Eclipse is using an old version of the file, likely because you edited the file outside of Eclipse. Just refresh the file (Right click / Refresh) and it should start working as you expect.

Use the -Dlog4j.debug property to output log4j-internal debugging information and see which logging configuration is really loaded on startup
You will get some information like this (for xml based configuration but I suppose you will get similar informations with property file configurations):
log4j: Trying to find [log4j.xml] using context classloader sun.misc.Launcher$AppClassLoader#11b86e7.
log4j: Using URL [file:/C:/develop/workspace/foobar/target/classes/log4j.xml] for automatic log4j configuration.
log4j: Preferred configurator class: org.apache.log4j.xml.DOMConfigurator
The 'log4j: Using URL ...' line comes from the LogManager class.

Hibernate suppress info messages

So I am not very experience in Java and I am creating a simple test project with Hibernate but I am gettinga lot of INFO messages on the console that I want to suppress. I am creating a Java SE program in Eclipse.
Now as I think I understand it then I need to control this in a log4j.properties file, and I seem to have found the appropiate config to use, but the problem is that it appears that it makes no difference!
My guess is that my log4j.properties file is somehow not being read. But all the details I have found say to place in in the root of my src directory, but it appears not to make any difference. And I have tried placing it in other places in my classpath but all with no luck.
Can somebody help me track down the issue and resolve this?
I had a similar issue last week with a jndi.properties files while using JMS. I eventually resolved that by I am guessing that I am doing something wrong in general. So any tips would be appreciated on where to place config/properties files.
Thanks.

log4j logging hierarchy order
OFF
FATAL
ERROR
WARN
INFO
DEBUG
TRACE
ALL
To suppress info messages ,you need to make log4j.properties as
#rootlogger specs
log4j.rootLogger=ERROR, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
set any other logger as OFF

Please initialize the log4j system properly. While running web service

Maybe it looks silly to ask this but I am confused. I referred to Configuring Log4j property but it doesn't seem to help.
I have written a simple web service HelloWorld. And while running it I am getting the error something like this :
log4j:WARN No appenders could be found for logger (org.apache.axis.transport.http.AxisServlet).
log4j:WARN Please initialize the log4j system properly.
I am not sure why its happening.
I am generating the web-service using Eclipse and deployed in Tomcat 6.0. I check on Axis Developer's Guide and according to them
log4j.configuration=log4j.properties
Use this system property to specify the name of a Log4J configuration file. If not specified, the default configuration file is log4j.properties. A log4j.properties file is provided in axis.jar.
I didn't find log4j.properties in the axis.jar.
Any help on this?

Those messages are something tricky, enough so that people created this to make it clearer:
https://issues.apache.org/bugzilla/show_bug.cgi?id=25747
What's tricky about them is that the warnings are written if Log4j can't find its log4j.properties (or log4j.xml) file, but also if the file is fine and dandy but its content is not complete from a configuration point of view.
The following paragraph is taken from here:
http://svn.apache.org/repos/asf/logging/log4j/tags/v1_2_9/docs/TROUBLESHOOT.html
Logging output is written to a target by using an appender. If no appenders are attached to a category nor to any of its ancestors, you will get the following message when trying to log:
log4j: No appenders could be found for category (some.category.name).
log4j: Please initialize the log4j system properly.
Log4j does not have a default logging target. It is the user's responsibility to ensure that all categories can inherit an appender. This can be easily achieved by attaching an appender to the root category.
You can find info on how to configure the root logger (log4j.rootLogger) in the log4j documentation, basically adding something as simple as this at the beginning of the file:
log4j.rootLogger=debug, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
This should clear those WARN messages you get on startup (make sure you don't already have an appender named stdout; also be carefull of what level you give the root logger, debug will be very verbose and every library in your app will start writing stuff to the console).
As about the log4j.properties/log4j.xml, I suggest you place this file in /WEB-INF/classes as it is important to have it exposed for different tweaks (activating/deactivating logs, changing log levels etc). You can have it inside a JAR in the classpath also (as you specified in your comment), but it will be enclosed in the archive (hopefully in the right place inside the archive) and won't be as easy to handle as if it were in /WEB-INF/classes.

You have to create your own log4j.properties in the classpath folder.

Well, if you had already created the log4j.properties you would add its path to the classpath so it would be found during execution. Yes, the thingy will search for this file in the classpath.
Since you said you looked into axis and didnt find one, I am assuming you dont have a log4j.properties, so here's a crude but complete example.
Create it somewhere and add to your classpath. Put it for example, in c:/proj/resources/log4j.properties
In your classpath you simple add .......;c:/proj/resources
# Root logger option
log4j.rootLogger=DEBUG, stdout, file
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Redirect log messages to a log file, support file rolling.
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=c:/project/resources/t-output/log4j-application.log
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

If the below statment is present in your class then your log4j.properties should be in java source(src) folder , if it is jar executable it should be packed in jar not a seperate file.
static Logger log = Logger.getLogger(MyClass.class);
Thanks,

Warning No appenders could be found for logger means that you're using log4j logging system, but you haven't added any Appenders (such as FileAppender, ConsoleAppender, SocketAppender, SyslogAppender, etc.) into your configuration file or the configuration file is missing.
There are three ways to configure log4j: with a properties file (log4j.properties), with an XML file and through Java code (rootLogger.addAppender(new NullAppender());).
If you've property file present (e.g. when installing Solr), you need to place this file within your classpath directory.
classpath
Here are some command suggestions how to determine your classpath value:
$ echo $CLASSPATH
$ ps wuax | grep -i classpath
$ grep -Ri classpath /etc/tomcat? /var/lib/tomcat?/conf
or from Java: System.getProperty("java.class.path").
Tomcat
If you're using Tomcat, you may place your log4j.properties into: /usr/share/tomcat?/lib/ or /var/lib/tomcat?/webapps/*/WEB-INF/lib/ folder.
Solr
For the reference, Solr log4j.properties looks like:
# Logging level
solr.log=logs/
log4j.rootLogger=INFO, file, CONSOLE
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%-4r [%t] %-5p %c %x \u2013 %m%n
#- size rotation with log cleanup.
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.MaxFileSize=4MB
log4j.appender.file.MaxBackupIndex=9
#- File to log to and log format
log4j.appender.file.File=${solr.log}/solr.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%-5p - %d{yyyy-MM-dd HH:mm:ss.SSS}; %C; %m\n
log4j.logger.org.apache.zookeeper=WARN
log4j.logger.org.apache.hadoop=WARN
# set to INFO to enable infostream log messages
log4j.logger.org.apache.solr.update.LoggingInfoStream=OFF

If you are using Logger.getLogger(ClassName.class) then place your log4j.properties file in your class path:
yourproject/javaresoures/src/log4j.properties (Put inside src folder)

You can configure log4j.properties like above answers, or use org.apache.log4j.BasicConfigurator
public class FooImpl implements Foo {
private static final Logger LOGGER = Logger.getLogger(FooBar.class);
public Object createObject() {
BasicConfigurator.configure();
LOGGER.info("something");
return new Object();
}
}
So under the table, configure do:
configure() {
Logger root = Logger.getRootLogger();
root.addAppender(new ConsoleAppender(
new PatternLayout(PatternLayout.TTCC_CONVERSION_PATTERN)));
}

Question about Log4jAppender

i have started learning something about log4j as so far its working fine here is the code from the log4j.property file
# Set root logger level to DEBUG and its only appender to A1.
log4j.rootLogger=DEBUG, A1,xml
# A1 is set to be a ConsoleAppender.
log4j.appender.A1=org.apache.log4j.ConsoleAppender
# A1 uses PatternLayout.
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%d [%t] %-5p %c - %m%n
# ${applicationRoot}/logs/xml.log
log4j.appender.xml=org.apache.log4j.RollingFileAppender
log4j.appender.xml.File=G:/TESTGEN/logs/xmlimpex.log
log4j.appender.xml.MaxFileSize=2MB
log4j.appender.xml.MaxBackupIndex=2
log4j.appender.xml.layout = org.apache.log4j.PatternLayout
log4j.appender.xml.layout.ConversionPattern=%p %t %c - %m%n
and its working perfectly fine printing on the console as well logging to the file.I am wondering is it possible to do something as follow
i want that i should be able to log everything on the console which what this log4j file is doing
but on the same time i want that in the log file which i have configured using RollingFileAppender should log entries only for warning and errors.
Please suggest me how i can do this
Thanks in advance
Umesh

log4j.rootLogger=DEBUG,A1
log4j.newlogger=WARN, XML
Log4j works in this way: You can create multiple loggers which fit in a hiearchy where the Root logger is always at the top. Loggers can inherit levels and appenders (if the additivity flag is on) from parent loggers.
In the example I gave you, the new logger that you created is triggered at a WARN level. It has as appenders XML but also A1 (which it inherited from the Root logger).
Note that if we hadn't set the level of newLogger, it would have inherited the level DEBUG.
Hiearchies in log4j work like in java packages (using dots) and rely on the logger names. Logger X is the parent of logger X.Y which is the parent of logger X.Y.Z. Logger X is always the child of the Root logger.
You can read more about this in the Log4j introduction

In the documentation of Log4net it says somewhere that you can set which levels to be handled from the appender.

Log4j for per class, how is precedence determined?

I'm trying to permit debug logging per a particular class using Log4j, and I've got the following:
log4j.rootLogger=stdout, daily
log4j.logger.com.mycompany.myapplication.mymodule=DEBUG
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{h:mm:ssa} %5p (%F:%L) - %m%n
log4j.appender.stdout.threshold=warn
log4j.appender.daily=org.apache.log4j.DailyRollingFileAppender
log4j.appender.daily.layout=org.apache.log4j.PatternLayout
log4j.appender.daily.layout.ConversionPattern=%d{h:mm:ssa} %5p (%F:%L) - %m%n
log4j.appender.daily.File=/some/file/path/stuff
log4j.appender.daily.DatePattern=MMdd'.log'
log4j.appender.daily.threshold=info
If this is the WEB-INF/classes/log4j.properties file as part of tomcat should debug messages from mycompany.myapplication.mymodule be seen or do the entries later in the file override it? (or am I changing the logging level per class completely wrong?)
Secondly, if a log4j.properties file is included in a jar file, do my settings in Tomcat override those?

You tell your class to log at level DEBUG but tell the appenders to ignore anything below WARN and INFO, so you won't see the log messages.
As for the order in which the log4j.properties will be discovered:
WEB-INF/classes
Any JAR in WEB-INF/lib
common/classes (in the tomcat directory)
Any JAR that you put into common/endorsed
Any JAR that you put into common/lib
shared/classes
Any JAR that you put into shared/lib
The discovery will stop with the first file found.

For your first question, I would say that log4j.appender.daily.threshold=info is a problem. I might not pick any DEBUG message.
Normally, we don't give a threshold to an appender, levels are configured for loggers.
I suggest you use the log4j.xml instead of the log4j.properties.
In addition to the useful validation, it adds some interesting features or default values.
I don't recall exactly which though...

Yes, you seem to be configuring your individual loggers correctly.
No, they will not be seen because you are declaring thresholds on both of your appenders which are above DEBUG:
log4j.appender.stdout.threshold=warn
log4j.appender.daily.threshold=info
As for "Secondly, if a log4j.properties file is included in a jar file, do my settings in Tomcat override those?", I'm not sure what you mean by this. log4j attempts to load a log4j.xml or log4j.properties from the classpath, and will use whichever it finds first. IIRC, entries in the shared lib folder of Tomcat supercede the classpath of each application. If you have a log4j configuration in both a jar in WEB-INF/lib and in a plaintext file in WEB-INF/classes, then you are essentially flipping a coin at runtime as to which will be used.

I think you have to give mymodule an appender, as in
log4j.logger.com.mycompany.myapplication.mymodule=DEBUG, Daily
log4j.additivity.com.mycompany.myapplication.mymodule=false
Also, if you set the additivity to false, you make sure messages get logged only
by the appender you specify.
The 'root' of a jar is normally not included in the CLASSPATH, so a log4j.properties within a jar should be invisible to the JVM.