Log4j File Appender Configuration

• Log4j File Appender Configuration Pdf
• Log4j Appender Example
• Log4j Configuration File Location
• Log4j File Appender Configuration Key
• Log4j2 File Appender Configuration

1. Jun 05, 2014  The log4j.xml file, how do you charge? Because until now I used the log4j.properties in each project and the idea is to use only one log4j.xml for multiple projects, I’m using Apache Tomcat as the application server.
2. Unless you are using facades between your code and log4j or custom appenders it should be enough. Then set the level of the logger pointing to your code path to something verbose, like debug, trace or even all. And set threshold param of the file appender to the same value.

Apache log4j provides Appender objects for printing logging messages to different destinations such as consoles, files, sockets, NT event logs, etc. Each Appender object has different properties associated with it, and these properties indicate the behavior of that object. Logging to a file. You can change the default log4j.properties configuration so that messages are logged only to a file or to both the console and a file. For example, you would change the above configuration to a configuration similar to this: # initialize root logger with level ERROR for stdout and fout log4j.rootLogger=ERROR,stdout,fout # set.

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..

JanuszJanusz

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:

Januszpolarbearpolarbear

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.

Peter LindPeter Lind

If you just get rid of everything (e.g. if you are in tests)

As per Apache Log4j FAQ page:

Why do I see a warning about 'No appenders found for logger' and 'Please configure log4j properly'?

Basic java programming pdf. © 2000 McGraw-Hill Introduction to Object-Oriented Programming with Java -Wu Chapter 2 - 3 The First Java Application A program to display a window on the screen. Java i About the Tutorial Java is a high-level programming language originally developed by Sun Microsystems and released in 1995. Java runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. This tutorial gives a complete understanding of Java.

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

kenorbkenorb

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

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.

JeeBeeJeeBee

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.

}

stones333stones333

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:

The set of possible levels are:

TRACE,

DEBUG,

INFO,

WARN,

ERROR and

FATAL

According to Logging Services manual

MathMath

To enable -Dlog4j.debug, I go to System, Advanced system settings, Environment variables and set system variable _JAVA_OPTIONS to -Dlog4j.debug.

kenorb

What are you developing in? Are you using Apache Tomcat?

I have a properties like this in a Java app of mine.

StevenStevenJanusz

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

Aybek KokanbekovAybek Kokanbekov

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.

As explained earlier there are 2 approaches

First one is to just add this line to your main method:

Log4j File Appender Configuration Pdf

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.

Shlomi

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.

atom88atom88

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.

1. 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

2. log4j_External.xml « XML log4j:configuration with public DTD file

3. Log4j Configuration from the URL in Java program:

In order to specify a custom configuration with an external file, the used class must implement the Configurator interface.

Resident evil 1 pc game. 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.

YashYash

The fix for me was to put 'log4j.properties' into the 'src' folder.

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.

Jacob

This is an alternative way using .yaml

Logic Structure:

Sample:

Ref: LOG4J 2 CONFIGURATION: USING YAML

emecasemecas

For testing, a quick-dirty way including setting log level:

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• log4j Tutorial

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To write your logging information into a file, you would have to use org.apache.log4j.FileAppender.

FileAppender Configuration

FileAppender has the following configurable parameters:

Property	Description
immediateFlush	This flag is by default set to true, which means the output stream to the file being flushed with each append operation.
encoding	It is possible to use any character-encoding. By default, it is the platform-specific encoding scheme.
threshold	The threshold level for this appender.
Filename	The name of the log file.
fileAppend	This is by default set to true, which means the logging information being appended to the end of the same file.
bufferedIO	This flag indicates whether we need buffered writing enabled. By default, it is set to false.
bufferSize	If buffered I/O is enabled, it indicates the buffer size. By default, it is set to 8kb.

Following is a sample configuration file log4j.properties for FileAppender −

Log4j Appender Example

If you wish to have an XML configuration file equivalent to the above log4j.properties file, then here is the content:

You can try log4j - Sample Program with the above configuration.

Logging in Multiple Files

You may want to write your log messages into multiple files for certain reasons, for example, if the file size reached to a certain threshold.

Log4j Configuration File Location

To write your logging information into multiple files, you would have to use org.apache.log4j.RollingFileAppender class which extends the FileAppender class and inherits all its properties.

We have the following configurable parameters in addition to the ones mentioned above for FileAppender −

Property	Description
maxFileSize	This is the critical size of the file above which the file will be rolled. Default value is 10 MB.
maxBackupIndex	This property denotes the number of backup files to be created. Default value is 1.

Following is a sample configuration file log4j.properties for RollingFileAppender.

If you wish to have an XML configuration file, you can generate the same as mentioned in the initial section and add only additional parameters related to RollingFileAppender.

This example configuration demonstrates that the maximum permissible size of each log file is 5 MB. Upon exceeding the maximum size, a new log file will be created. Since maxBackupIndex is defined as 2, once the second log file reaches the maximum size, the first log file will be erased and thereafter, all the logging information will be rolled back to the first log file.

You can try log4j - Sample Program with the above configuration.

Daily Log File Generation

There may be a requirement to generate your log files on a daily basis to keep a clean record of your logging information.

To write your logging information into files on a daily basis, you would have to use org.apache.log4j.DailyRollingFileAppender class which extends the FileAppender class and inherits all its properties.

There is only one important configurable parameter in addition to the ones mentioned above for FileAppender:

Property	Description
DatePattern	This indicates when to roll over the file and the naming convention to be followed. By default, roll over is performed at midnight each day.

Log4j File Appender Configuration Key

DatePattern controls the rollover schedule using one of the following patterns:

DatePattern	Description
'.' yyyy-MM	Roll over at the end of each month and at the beginning of the next month.
'.' yyyy-MM-dd	Roll over at midnight each day. This is the default value.
'.' yyyy-MM-dd-a	Roll over at midday and midnight of each day.
'.' yyyy-MM-dd-HH	Roll over at the top of every hour.
'.' yyyy-MM-dd-HH-mm	Roll over every minute.
'.' yyyy-ww	Roll over on the first day of each week depending upon the locale.

Log4j2 File Appender Configuration

Following is a sample configuration file log4j.properties to generate log files rolling over at midday and midnight of each day.

If you wish to have an XML configuration file, you can generate the same as mentioned in the initial section and add only additional parameters related to DailyRollingFileAppender.

You can try log4j - Sample Program with the above configuration.