Log4J Tutorial | What is Log4J?? | Log4J Explained in Detail

Log4J Tutorial

    Our Log4J tutorial is designed for both beginners and professionals. This tutorial will provide you all the basic concepts of Log4J like Log4J architecture, Log4J configuration, etc. It is a very fast, reliable, and flexible framework that is written in Java. It is an open-source logging library for Java. Easy login means a specific way to display system status during operation. Logs are used for the capture and persistence of important data and make it available for analysis at any time.

Log4J Tutorial

NOTE: To understand Log4J, you should have basic knowledge of Java.

Introduction

    1. Logging: Logging is a powerful tool for understanding and debugging the runtime behavior of any program. Easy login means a specific way to display system status during operation. Logs are used for the capture and persistence of important data and make it available for analysis at any time.

For better Logging, always keep three things in mind:

• Log messages should provide the necessary information to understand what the application is doing internally.
• Login file messaging should be as efficient as possible so as not to affect the performance of your application.
• You need to be able to adapt the details of logging to different feed locations and conditions.                

    2. Why use Log4J??

• It is open-source hence, free to use.
• With log4j, it is possible to store the flow information of our automation on file or archive.
• Log4j is used for large and small projects.
• In log4j, we use log statements rather than SOPL statements in code to determine project status while running.

    3. Features of Log4J??

• Supports international performance
• Prepared for speed
• It is based on a named logger program
• Safe with series
• Designed for different Java management from scratch 
• Not limited to a predefined set of resources
• Supports multiple appender output per blog
• The log output format can be easily changed by expanding the Layer class
• Logging behavior can be set during operation using the configuration file

    4. Advantages of Log4J??

Quick fix: Once we have identified a problem, we know exactly how to solve the problem. Well-designed and well-coded cutting code reduces the total cost of fixing errors in the operating system.

Problem Diagnosis: No matter how well our code is written, there may be some problems hidden in it. If you review the logging process, then we will be able to identify problems accurately and quickly.

Easy Fixing: An app with a useful cutting feature that is easy to repair and, therefore, easy to maintain.

Cost and Save Time: A well-coded logging code provides quick fixes and easy maintenance. It makes installation, daily repairs, and maintenance, and debugging more expensive and time-consuming.        

    5. Disadvantages of Log4J??

Login may extend the operating time due to the processing of login information and the input / output (I / O) device related to publishing login information. 

Login includes editing due to the additional code required to generate login information. The login process increases the code size. 

Details of poorly manufactured logging can be confusing. 

Signing in with malicious code could seriously disrupt the operation of the application. 

Lastly, logging requires advance planning, as entering a login code at the end of the development phase is difficult.

The architecture of Log4J??

    Log4J is a layered architecture where each layer has its own objects and their own work or performs a task. This layered architecture makes its design simple and reliable for future use and manipulation.

It has two objects in there architecture:

1. Core Objects: It has mandatory objects to use and all the objects are necessary to use this framework.
2. Support Objects: It has optional objects to use and these are used to perform important tasks of Core Objects.

    Types of Core Objects:

        1. Logger: 

Logger is a class, available at org.apache.log4j. *

We have to create one Logger object in each java section

The login section is used to enable log4j in our java class

Login methods are used to generate log statements in the java class instead of SOPLS.

In order to get a Logger class item, we need to call the factory stand method that will provide the object as a return type.

We should build a Logger object after the name of our class. For example:    

                Access point:

                static Logger log = Logger.getLogger (YourClassName.class.getName ()) 

            NOTE: When creating a login object, we need to pass the name of a fully qualified class object or class object as a parameter where the category specifies the current category in which log4j will use it.

        Some Methods of Logger are:

• debug()
• info()
• warn()
• error()
• fatal()                          

        2. Appender: The appender is part of the lower layer, which provides Appender properties. The Appender object is responsible for publishing login information to various selected sites such as files, website, console, Unix Syslog, etc.

• Logging classes are used to generate statements at various levels, and Appender takes these logs and stores them on a specific website or files.
• The appendix is not a category; it is a visible connector.

            Appender Implementation Classes:

• FileAppender: used to add log events to a file. Supports two classes over the appender:
• RollingFileAppender: Extends the FileAppender class to back up log files when they reach a certain size.
• DailyRollingFileAppender: Extends the FileAppender class so that the subfolder file is wrapped at a user-selected frequency.
• ConsoleAppender: Add log events to System. err or System. out using a user-defined structure. The default console is System. out.

• JDBCAppender: Used for Web.

• SMTPAppender: Used to send email in the event of a particular login incident, usually with fatal errors or errors.

• SocketAppender: Used for remote storage.

• SyslogAppender: Sends messages to the remote Syslog domain.

• TelnetAppender: Works exclusively on writing read-only socks. 

• WriterAppender: Used to add log events to Author or Output Stream depending on user preferences.

        3. Layout: The layout layer provides layout elements that are used to format entry information in different styles. Used to provide support for appender pre-publishing login information.

• Structural elements play an important role in publishing logging information in a way that is, both human-readable and reusable.

• The layout section describes the format in which log statements are written in the index area by the appendix.

            Types of Layout Classes:

• SimpleLayout: Used for output formatting in a very simple way; printer Level, then dash "-" and then log message.
• PatternLayout: Used for output based on a specified conversion pattern or if not specified, the default conversion pattern is considered.
• HTML layout: Format your output as an HTML table.
• XMLLayout

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