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Configuration: the root element of a log4j2 configuration file; the status attribute represents the level at which internal log4j events should be logged; Appenders: this element contains a list of appenders; in our example, an appender corresponding to the System console is defined; Loggers: this element contains a list of Logger instances. Example log4j Configuration File: Log4j « Language Basics « Java. /. # define the root logger with two appenders writing to console and file log4j.rootLogger = DEBUG, CONSOLE, FILE #define your own logger named com.foo log4j.logger.com.foo=com.foo.MyLogger #assign appender to your own logger log4j.logger.com.foo.appender=FILE #define. Log4j RollingFileAppender is an OutputStreamAppender that writes log messages to files, following a configured triggering policy when a backup should occur. Log4j.logger.com.vaannila.admin=,AdminFileAppender log4j.logger.com.vaannila.report=,ReportFileAppender Insted of applying a logger level, the field is left blank so the rootLogger level (' DEBUG.
After adding log4j to my application I get the following output every time I execute my application:
It seems this means a configuration file is missing.Where should this config file be located and what is a good start content?
I'm using plain java for developing a desktop application. So no webserver etc..
Janusz
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21 Answers
Log4j by default looks for a file called log4j.properties or log4j.xml on the classpath. You can control which file it uses to initialize itself by setting system properties as described here (Look for the 'Default Initialization Procedure' section).
For example:
Will cause log4j to look for a file called customName on the classpath.
If you are having problems I find it helpful to turn on the log4j.debug:
It will print to System.out lots of helpful information about which file it used to initialize itself, which loggers / appenders got configured and how etc.
The configuration file can be a java properties file or an xml file. Here is a sample of the properties file format taken from the log4j intro documentation page:
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While setting up log4j properly is great for 'real' projects you might want a quick-and-dirty solution, e.g. if you're just testing a new library.
If so a call to the static method
will setup basic logging to the console, and the error messages will be gone.
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If you just get rid of everything (e.g. if you are in tests)
user831217user831217
As per Apache Log4j FAQ page:
Why do I see a warning about 'No appenders found for logger' and 'Please configure log4j properly'?
This occurs when the default configuration files
log4j.properties
and log4j.xml
can not be found and the application performs no explicit configuration. log4j
uses Thread.getContextClassLoader().getResource()
to locate the default configuration files and does not directly check the file system. Knowing the appropriate location to place log4j.properties or log4j.xml
requires understanding the search strategy of the class loader in use. log4j
does not provide a default configuration since output to the console or to the file system may be prohibited in some environments.Basically the 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());
).log4j.properties
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 in Linux how to determine your classpath value:
or from Java:
System.getProperty('java.class.path')
.Log4j XML
Below is a basic XML configuration file for log4j in XML format:
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 default
log4j.properties
file looks like:Why can't log4j find my properties file in a J2EE or WAR application?
The short answer: the log4j classes and the properties file are not within the scope of the same classloader.
Log4j only uses the default
Class.forName()
mechanism for loading classes. Resources are handled similarly. See the documentation for java.lang.ClassLoader
for more details.So, if you're having problems, try loading the class or resource yourself. If you can't find it, neither will log4j. ;)
See also:
- Short introduction to log4j at Apache site
- Apache: Logging Services: FAQ at Apache site
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You can set the location of your log4j.properties from inside your java app by using:
More information is available here: https://logging.apache.org/log4j/1.2/manual.html
ArashArash
Find a log4j.properties or log4j.xml online that has a root appender, and put it on your classpath.
will log to the console. I prefer logging to a file so you can investigate afterwards.
although for verbose logging applications 100KB usually needs to be increased to 1MB or 10MB, especially for debug.
Personally I set up multiple loggers, and set the root logger to warn or error level instead of debug.
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Another way to do it without putting the property file on the classpath, is to set the property from the java code directly. Here is the sample code.
}
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You can set up the log level by using setLevel().
The levels are useful to easily set the kind of informations you want the program to display.
For example:
Log4j Console Appender
The set of possible levels are:
TRACE,
DEBUG,
INFO,
WARN,
ERROR and
FATAL
According to Logging Services manual
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To enable
kenorb-Dlog4j.debug
, I go to System, Advanced system settings, Environment variables and set system variable _JAVA_OPTIONS
to -Dlog4j.debug
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Feng ZhangFeng Zhang
What are you developing in? Are you using Apache Tomcat?
I have a properties like this in a Java app of mine.
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KanishkKanishk
I've created file log4j.properties in resources folder next to hibernate.cfg.xml file and filled it with text below:
now I got rid of warnings and errors
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Simply, create log4j.properties under src/main/assembly folder. Depending on if you want log messages to be shown in the console or in the file you modify your file. The following is going to show your messages in the console.
NSonmezNSonmez
As explained earlier there are 2 approaches
First one is to just add this line to your main method:
Second approach is to add this standard log4j.properties file to your classpath:
While taking second approach you need to make sure you initialize the file properly.
Eg.
Make sure you create required folder to store log files.
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AkashKAkashK
Try to set debug attribut in log4j:configuration node to true.
It prints out information as the configuration file is read and used to configure the log4j environment. You may be got more details to resolve your problem.
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Logging API - The Java Logging API facilitates software servicing and maintenance at customer sites by producing log reports suitable for analysis by end users, system administrators, field service engineers, and software development teams. The Logging APIs capture information such as security failures, configuration errors, performance bottlenecks, and/or bugs in the application or platform. The core package includes support for delivering plain text or XML formatted log records to memory, output streams, consoles, files, and sockets. In addition, the logging APIs are capable of interacting with logging services that already exist on the host operating system.
Package java.util.logging « Provides the classes and interfaces of the Java platform's core logging facilities.
Log4j 1.x « log4j is a popular Java-based logging utility. Log4j is an open source project based on the work of many authors. It allows the developer to control which log statements are output to a variety of locations by using Appenders [console, files, DB and email]. It is fully configurable at runtime using external configuration files.
Log4j has three main components:
- Loggers - [OFF, FATAL, ERROR, WARN, INFO, DEBUG, TRACE]
- Appenders
- Apache Commons Logging: ConsoleAppender, FileAppender, RollingFileAppender, DailyRollingFileAppender, JDBCAppender-
Driver
, SocketAppender - Log4J Appender for MongoDB:MongoDbAppender -
Driver
- Layouts - [PatternLayout, EnhancedPatternLayout]
Configuration files can be written in XML or in Java properties (key=value) format.
- log4j_External.properties « Java properties (key=value) format
The string between an opening '${' and closing '}' is interpreted as a key. The value of the substituted variable can be defined as a system property or in the configuration file itself. Set appender specific options. « log4j.appender.appenderName.option=value, For each named appender you can configure its Layout.
MySQL Table structure for table
logdata
- log4j_External.xml « XML log4j:configuration with public DTD file
- Log4j Configuration from the URL in Java program:
Log4j2 File Appender Configuration
In order to specify a custom configuration with an external file, the used class must implement the Configurator interface.
The faces of the dice slides are coated in real life with a thin nonskid material, similar to Gecko pads (used generally for rugs, as to not slip on them); this is to force the dice to roll and not just slide on the slides. Pdf of dice tower templates.
when default configuration files 'log4j.properties', 'log4j.xml' are not available
- For 'log4j.properties' you can fed to the PropertyConfigurator.configure(java.net.URL) method.
- For 'log4j.xml' DOMConfigurator will be used.
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Dr mario download. The fix for me was to put 'log4j.properties' into the 'src' folder.
SilverSilver
If we are using apache commons logging wrapper on top of log4j, then we need to have both the jars available in classpath. Also,
commons-logging.properties
and log4j.properties/xml
should be available in classpath. We can also pass implementation class and
log4j.properties
name as JAVA_OPTS
either using -Dorg.apache.commons.logging.Log=<logging implementation class name> -Dlog4j.configuration=<file:location of log4j.properties/xml file>
. Same can be done via setting JAVA_OPTS
in case of app/web server.It will help to externalize properties which can be changed in deployment.
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ShivShiv
This is an alternative way using .yaml
Logic Structure:
Sample:
Itunes windows xp 32. Ref: LOG4J 2 CONFIGURATION: USING YAML
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For testing, a quick-dirty way including setting log level:
Log4j Configuration File Location
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