{"id":14883,"date":"2014-09-30T15:00:00","date_gmt":"2014-09-30T12:00:00","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=14883"},"modified":"2014-09-30T10:16:32","modified_gmt":"2014-09-30T07:16:32","slug":"log4j-rootlogger-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/java-development\/enterprise-java\/log4j\/log4j-rootlogger-example\/","title":{"rendered":"log4j rootlogger example"},"content":{"rendered":"

In this example we shall talk about the rootlogger<\/code>, which is a basic component in Log4j<\/a><\/code>. Log4j a thread-safe and flexible logging library for Java, licensed under the Apache Software Foundation.<\/p>\n

The basic components of the log4j architecture are the loggers<\/code>, the appenders<\/code> and the layouts<\/code>. Loggers<\/code> are used to log the messages, appenders<\/code> to publish the messages to different outputs and layouts<\/code> to format the log messages. All these components are configured in the log4j.properties<\/code> file, which is placed in the application classpath<\/code>. <\/p>\n

The basic logger that sits at the top of the logger hierarchy is the rootlogger<\/code>. RootLogger<\/code><\/a> is a regular logger, although it cannot be assigned a null<\/code> level and since it cannot have a parent, the getChainedLevel()<\/code> API method always returns the value of the level field without walking the hierarchy. Also, the rootLogger<\/code> cannot be retrieved by name. It can only be retrieved by invoking the static getRootLogger()<\/code> API method of Logger<\/code><\/a>. All other loggers are instantiated and retrieved with the class static getLogger(String name)<\/code> API method of Logger<\/code><\/a>, which takes the name of the desired logger as a parameter. <\/p>\n

Below, we have created an example with a class that uses the rootlogger<\/code> to log messages to the console. <\/p>\n

Tip<\/strong>
You may skip project creation and jump directly to the beginning of the example<\/strong><\/a> below.<\/div>\n

Our preferred development environment is Eclipse<\/a>. We are using Eclipse Juno (4.2) version, along with Maven<\/a> Integration plugin version 3.1.0. You can download Eclipse from here<\/a> and Maven Plugin for Eclipse from here<\/a>. The installation of Maven plugin for Eclipse is out of the scope of this tutorial and will not be discussed. We are also using the JDK 7_u_21.<\/p>\n

Let’s begin,<\/p>\n

1. Create a new Maven project<\/h2>\n

Go to File -> Project ->Maven -> Maven Project.<\/p>\n

\"New<\/a>
New Maven Project – step 1<\/figcaption><\/figure><\/p>\n

In the “Select project name and location” page of the wizard, make sure that “Create a simple project (skip archetype selection)” option is checked<\/strong>, hit “Next” to continue with default values.<\/p>\n

\"New<\/a>
New Maven Project 2<\/figcaption><\/figure>
<\/div> <\/div><\/p>\n

In the “Enter an artifact id” page of the wizard, you can define the name and main package of your project. We will set the “Group Id” variable to \"com.javacodegeeks.snippets.enterprise\"<\/code> and the “Artifact Id” variable to \"log4jexample\"<\/code>. The aforementioned selections compose the main project package as \"com.javacodegeeks.snippets.enterprise.log4jexample \"<\/code> and the project name as \"log4jexample\"<\/code>. Hit “Finish” to exit the wizard and to create your project.<\/p>\n

\"log4j<\/a>
log4j example<\/figcaption><\/figure><\/p>\n

The Maven project structure is shown below:<\/p>\n

\"log4j<\/a>
log4j example structure<\/figcaption><\/figure><\/p>\n