Debug Info Warn Error Fatal Log4j
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All Implemented Interfaces: Serializable Direct Known Subclasses: UtilLoggingLevel public class Levelextends
Log4j Levels Order
Priorityimplements Serializable Defines the minimum set of log levels log4j levels recognized by the system, that is OFF, FATAL, ERROR, WARN,
Log4j Trace
INFODEBUG and ALL. The Level class may be subclassed to define a larger level set. Author: Ceki Gülcü log4j2 log levels See Also:Serialized Form Field Summary staticLevel ALL The ALL has the lowest possible rank and is intended to turn on all logging. staticLevel DEBUG The DEBUG Level designates logger levels java fine-grained informational events that are most useful to debug an application. staticLevel ERROR The ERROR level designates error events that might still allow the application to continue running. staticLevel FATAL The FATAL level designates very severe error events that will presumably lead the application to abort. staticLevel INFO The INFO level designates informational messages that highlight the progress of the application at coarse-grained level. staticLevel OFF The OFF has the highest possible rank and is intended to turn off logging. staticLevel TRACE The TRACE Level designate
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Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like https://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html you, helping each other. Join them; it only takes a minute: Sign up Difference between logger.info and logger.debug up vote 40 down vote favorite 21 What is the difference between logger.debug and logger.info ? When will logger.debug be printed? java logging log4j share|improve this question edited Sep 25 '14 at 17:48 Oliver Lloyd 3,15042148 asked Feb http://stackoverflow.com/questions/2342280/difference-between-logger-info-and-logger-debug 26 '10 at 14:33 Senthilnathan 287258 add a comment| 5 Answers 5 active oldest votes up vote 10 down vote accepted This will depend on the logging configuration. The default value will depend on the framework being used. The idea is that later on by changing a configuration setting from INFO to DEBUG you will see a ton of more (or less if the other way around) lines printed without recompiling the whole application. If you think which one to use then it boils down to thinking what you want to see on which level. For other levels for example in Log4J look at the API, http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html share|improve this answer answered Feb 26 '10 at 14:38 toomasr 2,73211830 add a comment| up vote 78 down vote I suggest you look at the article called "Short Introduction to log4j". It contains a short explanation of log levels and demonstrates how they can be used in practice. The basic idea of log levels is that you want to be able
log4j - Configuration log4j - Sample Program log4j - Logging Methods log4j - Logging Levels log4j - Log Formatting log4j - Logging in Files log4j - Logging in Database log4j Useful Resources log4j - https://www.tutorialspoint.com/log4j/log4j_logging_levels.htm Questions and Answers log4j - Quick Guide log4j - Useful Resources log4j - Discussion Selected Reading Developer's Best Practices Questions and Answers Effective Resume Writing HR Interview Questions Computer Glossary Who is Who log4j http://javapapers.com/log4j/log4j-levels/ - Logging Levels Advertisements Previous Page Next Page The org.apache.log4j.Level levels. You can also define your custom levels by sub-classing the Level class. Level Description ALL All levels including custom levels. DEBUG Designates log level fine-grained informational events that are most useful to debug an application. ERROR Designates error events that might still allow the application to continue running. FATAL Designates very severe error events that will presumably lead the application to abort. INFO Designates informational messages that highlight the progress of the application at coarse-grained level. OFF The highest possible rank and is intended to turn off logging. TRACE Designates finer-grained informational events debug info warn than the DEBUG. WARN Designates potentially harmful situations. How do Levels Works? A log request of level p in a logger with level q is enabled if p >= q. This rule is at the heart of log4j. It assumes that levels are ordered. For the standard levels, we have ALL < DEBUG < INFO < WARN < ERROR < FATAL < OFF. The Following example shows how we can filter all our DEBUG and INFO messages. This program uses of logger method setLevel(Level.X) to set a desired logging level: This example would print all the messages except Debug and Info: import org.apache.log4j.*; public class LogClass { private static org.apache.log4j.Logger log = Logger.getLogger(LogClass.class); public static void main(String[] args) { log.setLevel(Level.WARN); log.trace("Trace Message!"); log.debug("Debug Message!"); log.info("Info Message!"); log.warn("Warn Message!"); log.error("Error Message!"); log.fatal("Fatal Message!"); } } When you compile and run the LogClass program, it would generate the following result − Warn Message! Error Message! Fatal Message! Setting Levels using Configuration File log4j provides you configuration file based level setting which sets you free from changing the source code when you want to change the debugging level. Following is an example configuration file which would perform the same task as we did using the log.s
and layout. Logger takes care of the logging mechanism and deals with level of logging. Log4j provides five standard levels of logging. There are two more special levels given by log4j. Above all these, log4j allows you to create custom levels. Five standard log4j levels DEBUG Level This log4j level helps developer to debug application. Level of message logged will be focused on providing support to a application developer. INFO Level This log4j level gives the progress and chosen state information. This level will be generally useful for end user. This level is one level higher than DEBUG. WARN Level This log4j level gives a warning about an unexpected event to the user. The messages coming out of this level may not halt the progress of the system. ERROR Level This log4j level gives information about a serious error which needs to be addressed and may result in unstable state. This level is one level higher than WARN. FATAL Level This log4j level is straightforward and you don't get it quite often. Once you get this level and it indicates application death. Two special log4j levels ALL Level This log4j level is used to turn on all levels of logging. Once this is configured and the levels are not considered. OFF Level This log4j level is opposite to ALL level. It turns off all the logging. New Trace Level added in Log4j TRACE Level This log4j level gives more detailed information than the DEBUG level and sits top of the hierarchy. This level is introduced from version 1.2.12 in log4j. Custom log4j levels Log4j's levels are mostly sufficient for all common applications. Rarely you may need a new Level apart from the levels provided by log4j. In that case you can extend org.apache.log4j.Level class and have your own custom level implementation. Log4j Logger Output When a logger is created, generally you assign a level. The logger outputs all those messages equal to that level and also all greater levels than it. So the order for the standard log4j levels are: Log4J Levels TRACE Level DEBUG Level INFO Level WARN Level ERROR Level FATAL Level TRACE Level Y Y Y Y Y Y DEBUG Level N Y Y Y Y Y INFO Level