a java logging framework is a computer data logging package for the java platform .

logging refers to the recording of activity .

logging is a common issue for development teams .

several frameworks ease and standardize the process of logging for the java platform .

this article covers general purpose logging frameworks .

java logging framework

: used to pass logging requests between the logging framework and individual log handlers .
apache commons logging is not really a logging framework , but it wraps over any one logging framework in it . more details can be found at
native code that wishes to use the java logging mechanisms should make normal jni calls into the java logging apis .
tinylog is a lightweight open - source logging framework for java and android , optimized for ease of use .
java . util . logging . logger ; / * * * an example of using the java . util . logging
handlers = java . util . logging . consolehandler . level = info java . util . logging . filehandler . pattern = % h / java % u . log java . util . logging . filehandler . limit = 50000 java . util . logging . filehandler . count = 1 java . util . logging . filehandler . formatter = java . util . logging . xmlformatter java . util . logging . consolehandler . level = info java . util . logging . consolehandler . formatter = java . util . logging . simpleformatter com . xyz . foo . level = severe
logrecord objects are used to pass logging requests between the logging framework and individual log handlers .
to bridge slf4j for a logging framework , you must include the plugin and logging framework dependencies in the dependencies list of your pom . xml file .
the java . util . logging package provides the logging capabilities via the logger class .
… then the choice of logging framework is not your responsibility and you should use a logging shim .
all of the logging class are in the java . * part of the namespace , in the java . util . logging package .
. level = info handlers = java . util . logging . consolehandler java . util . logging . consolehandler . formatter = java . util . logging . simpleformatter java . util . logging . consolehandler . level = all org . apache . http . level = finest
binding for java . util . logging , also referred to as jdk 1 . 4 logging
note that this commons logging bridge is only meant to be used for framework logging purposes , both in the core framework and in extensions . for applications , prefer direct use of log4j / slf4j or java . util . logging .
java logging . this article describes how to use the logging api in java programs . it includes an example for creating an html logger .
get the splunk java logging framework from github and clone the resources to your computer . for example , use the following command :
. level = info handlers = java . util . logging . consolehandler java . util . logging . consolehandler . formatter = java . util . logging . simpleformatter java . util . logging . consolehandler . level = all org . apache . http . impl . conn . level = finest
your problem is more than likely not with the logging framework but with the layout .
this class provides the basic functionality required by the logging framework for a target implementation .
assume you know how to setup your classpath to use your preferred logging framework implementation .
this tutorial provides an introduction to the java util logging framework to provide structured logging for your application . remember that this is only the most basic usage of the logging framework , and much more complex capabilities exist , including file - based configuration , network logging , and event - based logging .
the splunk java logging framework is licensed under the creative commons 3 . 0 license . details can be found in the file license .
not the answer you ' re looking for ? browse other questions tagged java logging log4j slf4j java . util . logging or ask your own question .
github - kadary / java - logger : a simple and powerful logging framework to use as an alternative to log4j , javautillogging . . .
the simple logging facade for java ( slf4j ) serves as a simple facade or abstraction for various logging frameworks ( e . g . java . util . logging , logback , log4j ) allowing the end user to plug in the desired logging framework at deployment time .
splunk logging for java includes several examples of configuration files in src / test / resources folder . for instance java . util . logging configuration looks like :
get the splunk java logging framework from github ( urltoken ) and clone the resources to your computer . for example , use the following command :
in addition , the logging framework does not attempt to protect itself against denial of service attacks . any given logging client can flood the logging framework with meaningless messages in an attempt to conceal some important log message .
java util logging comes from the school of thought that logging should be the exception and not the norm .
java util logging performance is significantly affected by the lack of a buffered handler .
for an overview of control flow , please refer to the java logging overview .
a simple and powerful logging framework to use as an alternative to log4j , javautillogging . . .
. level = info handlers = java . util . logging . consolehandler java . util . logging . consolehandler . formatter = java . util . logging . simpleformatter java . util . logging . consolehandler . level = all org . apache . http . level = finest org . apache . http . wire . level = severe
slf4j provides a common interface and abstraction for most of the java logging frameworks . it acts as a facade and provides standardized api for accessing the underlying features of the logging framework .
java is blessed with three big java logging frameworks : java util logging , log4j 2 , and logback . when picking one for your project , did you ever wonder about their performance ? after all , it would be silly to slow down the application just because you picked a sluggish logging framework or a suboptimal configuration .
by implementing some simple interfaces commons logging can be extended to support basically any other custom logging framework . commons logging tries to automatically discover the logging framework to use . if it fails to select the expected one , you must configure commons logging by hand . please refer to the commons logging documentation for more information .
slf4j supports popular logging frameworks , namely log4j , java . util . logging , simple logging and nop . the logback project supports slf4j natively .
org . apache . commons . logging ( spring framework 5 . 0 . 0 . rc3 api )
in this blog on log4j in java tutorial series we come across the basic introduction to logging in java , we come to know components and functioning of logging and all possible logging solutions to implement . in
see also should new projects use logback instead of log4j ? , what’s up with logging in java ? , which log4j facade to choose ? , find a way in the java logging frameworks scene . and do you find java . util . logging sufficient ? . ( spoiler : you shouldn ' t use java . util . logging , pretty please )
java util logging does not support the abbreviated logger naming strategy , so these benchmarks use a custom formatter which has the side effect of boosting the performance of java util logging .
slf4j so called simple logging facade for java ( slf4j ) is a java logging api based on single façade pattern . the logging backend is determined at compile time , this makes it easy to reduce coupling between application and logging framework . slf4j is a smart choice whenever you decided to integrate with existing or a third party api for logging .
the client library uses slf4j for all logging . if you want to turn on logging , you must include a plugin that bridges slf4j with a concrete logging framework .
since jdk 1 . 4 there has been a package java . util . logging that provides a logging framework similar to log4j . by default it reads a config file from $ java _ home / jre / lib / logging . properties which looks like this ( comments stripped ) :
provides the classes and interfaces of the java tm 2 platform ' s core logging facilities .
if you wish to use java . util . logging as the underlying logging framework , all you need to do is to declare
org . slf4j : slf4j - jdk14
as a dependency in your
java contains the java logging api . this logging api allows you to configure which message types are written . individual classes can use this logger to write messages to the configured log files .
i was thinking recently about logging in java , and how there are numerous logging frameworks ( maybe even too many ? ) that can help you with this . now , you’re not obliged to use a framework , and even though java’s standard code base includes logging almost nobody seems to use it . most developers lean towards using an external framework to help them log information at runtime .
embarrassingly , but looks like java . util . logging can ' t do this . . .
httpclient performs three different kinds of logging : the standard context logging used within each class , http header logging and full wire logging .
an slf4j binding designates an artifact such as slf4j - jdk14 . jar or slf4j - log4j12 . jar used to bind slf4j to an underlying logging framework , say , java . util . logging and respectively log4j .
commons logging can delegate to a variety of loggers for processing the actual output . below are configuration examples for commons logging , log4j and java . util . logging .
changing from one logging framework to another is typically a simple search and replace , or worst case a more advanced “structural” search and replace available in more advanced ides . if logging performance is important to you , the logging framework’s idiomatic logging api will always out - perform a shim and given that the cost of switching is lower than with other apis , you are probably better off coding direct to the logging framework .
java util logging cannot be recommended based on performance . the lack of a buffered handler implementation has a significant impact on logging performance .
spring ' s variant of the commons logging api : with special support for log4j 2 , slf4j and java . util . logging .
the logging configuration can be initialized using a logging configuration file that will be read at startup . this logging configuration file is in standard java . util . properties format .
appenders for http event collector for pushing from logback , log4j 2 and java . util . logging .
the framework at the last handover the formatted messages from formatter to handler or adapter .
as for the actual logging framework log4j ( 52 % ) remains the most widely used logger , with logback ( 29 % ) on it’s tail . it may surprise you that 7 % of the people that use a logger actually write the logging framework themselves . that’s about the same amount that use jul ( java . util . logging ) . jboss logging , the logging framework that is used in almost anything that is build at redhat or jboss , only has a market share of 1 % .
for example , if you want to use the log4j logging framework , add the following to your pom . xml file .
. level = info handlers = java . util . logging . consolehandler java . util . logging . consolehandler . formatter = java . util . logging . simpleformatter java . util . logging . consolehandler . level = all org . apache . http . impl . conn . level = finest org . apache . http . impl . client . level = finest org . apache . http . client . level = finest
commons . logging is providing a minimal set of logging functionality , hiding away additional functionality that the underlying framework might provide . you won ' t get advanced features like parameterized logging or the mdc .
java . util . logging has many curious peculiarities . you can add a facade api to tweak its behaviors
$ java _ home / java - djava . util . logging . config . file = $ home / myapp / logging . properties - classpath $ home / myapp / target / classes com . myapp . main
once the framework receives log messages it called formatter to format the messages in output form .
urltoken - logs to stderr . the log4j framework will use this configuration file by default .
log4j 2 is new and improved version of the log4j logging framework . the most compelling improvement is the possibility of asynchronous logging . log4j 2 requires the following libraries :
an introduction to the java logging api , brian gilstrap ( onjava . com , june 2002 ) talks about the use of the standard logging api ]
not the answer you ' re looking for ? browse other questions tagged java logging encapsulation slf4j apache - commons - logging or ask your own question .
the default java . util . logging . simpleformatter doesn ' t have the ability to log thread name at all . the java . util . logging . filehandler supports few template placeholders , none of them is thread name .
not the answer you ' re looking for ? browse other questions tagged java logging or ask your own question .
apache log4j is a java based logging utility and is under apache software foundation . log4j is very popular logging framework of today . log4j supports off , fatal , error , warn , info , debug and trace log levels . log4j can be configured in three ways - property file , xml file or through java code .
the desired logging framework can be plugged in at deployment time by inserting the appropriate jar file ( binding ) on your class path .
slf4j supports mdc , or mapped diagnostic context . if the underlying logging framework offers mdc functionality , then slf4j will delegate to the underlying framework ' s mdc . note that at this time , only log4j and logback offer mdc functionality . if the underlying framework does not offer mdc , for example java . util . logging , then slf4j will still store mdc data but the information therein will need to be retrieved by custom user code .
mapped diagnostic context
is essentially a map maintained by the logging framework where the application code provides key - value pairs which can then be inserted by the logging framework in log messages . mdc data can also be highly helpful in filtering messages or triggering certain actions .
log4j came to the rescue . it was everything one could ever want from a logging framework . it invented many concepts still used in today’s logging frameworks ( it was the first framework i used so please bear with me if a concept was not invented by it ) :
to quickly get you started and to serve as an example of how to do this , each example distribution uses the log4j framework , and includes sample urltoken and urltoken files that show how you might configure logging if you decide to use log4j as your concrete logging framework .
in this particular blog we will learn , what is logging ? , types of logging in java and a brief introduction to log4j and its functionality overview .
in order to try and be as fair to each logging framework , the benchmarks have been divided up by logging format . each logging framework has a default layout for their log messages , so by comparing all the frameworks using all the default layouts we get to see the best like - for - like comparisons .
java logging api is an pre build logging solution provided under java . util . logging . the logging api captures information of security failures , configuration errors , performance bottlenecks , and bugs in the application or platforms . the api is capable of delivering logs information on console , xml and store in a file format .
there are a number of strawmen implementations here to check the side - effects of various choices that can be made by a logging framework .
we use slf4j for logging . this means you can choose any slf4j - compliant logging framework such as logback , avsl , jdk logging , log4j , or simple . if you don ' t know which to choose , we recommend logback since it is a native implementation and the easiest to configure . please follow the instructions on the slf4j website to configure your logging framework . it should take no more than 15 minutes . once your logging framework is configured with slf4j , you should be able to see and manage logging from the java - client api . this is especially important for long - running querybatcher and writebatcher jobs .
the purpose of this project is to create a logging framework to allow developers to as seamlessly as possible integrate splunk best practice logging semantics into their code and easily send their log events to splunk . there are also custom handler / appender implementations and config examples for the most prevalent java logging frameworks in play .
java . util . logging . filehandler . count specifies how many output files to cycle through ( defaults to 1 ) .
logging is a basic need when you create software . logging use - cases are :
java util logging is using a custom format that is more optimized and unwinds some of the issues with java util logging , bringing it nearer to the performance of the other frameworks when unbuffered . the performance is still behind that of the other frameworks .
java . util . logging . filehandler . pattern specifies a pattern for generating the output file name . see below for details . ( defaults to
% h / java % u . log
) .
this article discusses the most popular java logging frameworks , log4j 2 and logback , along with their predecessor log4j , and briefly touches upon slf4j , a logging facade that provides a common interface for different logging frameworks .
the simple logging facade for java ( slf4j ) serves as a simple facade or abstraction for various logging frameworks , such as java . util . logging , logback and log4j . slf4j allows the end - user to plug in the desired logging framework at deployment time . note that slf4j - enabling your library / application implies the addition of only a single mandatory dependency , namely slf4j - api - 1 . 8 . 0 - beta2 . jar .
an extremely fast java logger , using chronicle queue as persistence engine . we feel the logging should not slow down your system .
the wrapper won ' t conflict with a framework you happen to deploy on , so you could swap the framework with a non conflicting one and only affect the wrapper . regarding the call location feature , it depends on how you implement it and the framework involved . we were able to do it with log4j without issues .
the modern way is to use dependency injection to set dependencies , such as the logging interface to use , which this pattern supports . so no modern logging framework is likely to do things differently .
tinylog can be configured by system properties , properties files and a fluent java api .
to create a logger in your java code , you can use the following snippet .
explain to your architecture astronaut that slf4j already can act as a wrapper for other logging implementations , like log4j . so if you need to use some other logger in the future and there is no adapter for slf4j , you can write it when the need arises , but it will just be the adapter , instead of writing a whole logging framework that will just wrap some other logging framework and you need to design your framework for that and write your own adapter .
java . util . logging . filehandler . append specifies whether the filehandler should append onto any existing files ( defaults to false ) .
add the splunk logging for java library to your project . if you are using maven , add the following to your dependencies section :
you can find help through our community on splunk answers ( use the logging - library - java tag to identify your questions ) .
logger is an object that is responsible to capture event messages from the application and passes them to the framework .
add the logging framework you plan to use . the three big ones in use today are logback , log4j 2 . x , and java . util . logging ( which comes with your jdk ) . if you are using maven , add the corresponding dependencies below to your pom . xml :
ok , let’s benchmark the different logging frameworks then . there is a lot that you can mess up when trying to write micro - benchmarks in java . the wise java engineer knows to use jmh for micro - benchmarking .
loggers are normally named entities , using dot - separated names such as
java . awt
. the namespace is hierarchical and is managed by the logmanager . the namespace should typically be aligned with the java packaging namespace , but is not required to follow it slavishly . for example , a logger called
java . awt
might handle logging requests for classes in the java . awt package , but it might also handle logging for classes in sun . awt that support the client - visible abstractions defined in the java . awt package .
in order to measure the cost / benefit of using a general utility logging framework , for each set of benchmarks i have written at least one strawman logging implementation . the strawmen implementations are free to make optimizations that are not available for a general utility logging framework and can therefore be used to measure the upper limit of performance in order to obtain the required minimal functionality .
logging frameworks should provide significantly better documentation on how to configure logging . ideally , they should provide examples of the best configurations for logging to :
in case an externally - maintained component you depend on uses a logging api other than slf4j , such as commons logging , log4j or java . util . logging , have a look at slf4j ' s binary - support for legacy apis .
the level class defines a set of standard logging levels that can be used to control logging output . the logging level objects are ordered and are specified by ordered integers . enabling logging at a given level also enables logging at all higher levels .
@ connolly _ s @ rmannibucau the logging situation in java is still so screwed up . millions of dollars are lost on this ridiculous problem .
java . util . logging . filehandler . encoding the name of the character set encoding to use ( defaults to the default platform encoding ) .
this project provides utilities to easily log data using splunk ' s recommended best practices to any supported logger , using any of the three major java logging frameworks ( logback , log4j 2 , and java . util . logging ) , to the http event collector and to splunk tcp inputs .
the level class defines a set of standard logging levels that can be used to control logging output .
for the actual logging framework apache log4j is the most used with logback right on it’s tail . which is a good thing for logback that is really the successor of log4j .
this provides us with the opportunity to use a custom java util logging formatter that will allow us to see where some of the issues with java util logging performance originate from . in order to maximize the utility of the comparison we also include results of the other frameworks when using an unbuffered appender .
the logging apis are described in detail in the java se api specification . the goal of this document is to provide an overview of key elements .
i had similar problem . as answered here how to align log messages using java . util . logging you can extend java . util . logging . formatter but instead getting logrecord # getthreadid ( ) you can get thread name by invoking thread . currentthread ( ) . getname ( ) like this :
the logging package is an ultra - thin bridge between different logging implementations . a library that uses the commons - logging api can be used with any logging implementation at runtime . commons - logging comes with support for a number of popular logging implementations , and writing adapters for others is a reasonably simple task .
sooner or later , however , you will reach the point where you have to make the choice of logging framework . in 2017 we can break down the choice into 4 options :
this article shows very simple examples of how you can use different logging framework such as log4j , log4j2 and logback . it covers simple configuration examples for all of the mentioned frameworks .
if you wish to use log4j as the underlying logging framework , all you need to do is to declare
org . slf4j : slf4j - log4j12
as a dependency in your
finally , the lead programer from log4j quit the project for reasons i will not detail here . he created another logging framework , namely slf4j , that should have been log4j v2 .
the main purpose of the 1 . 2 release is to drop support for java 1 . 1 .
based on performance , java util logging cannot be recommended for this output format . there is no significant difference between log4j or logback in terms of performance .
for example , the memoryhandler uses a property
java . util . logging . memoryhandler . size
to determine the default size for its ring buffer .
in this post , i will ramble on logging in java , how it was done in the old days and what a library like slf4j can bring .
sending logging to operating system level logging systems , e . g . syslog , windows event log , etc
as mentioned previously , slf4j supports various logging frameworks . the slf4j distribution ships with several jar files referred to as
slf4j bindings
, with each binding corresponding to a supported framework .
people use java ' s logging mostly because they don ' t want to have 3rd party dependencies . that ' s also why they can ' t depend on existing logging facades like apache ' s or slf4j .
in the end , some believe there should be just a single standard built in as a java standard .
is it possible to print thread name in the log statements generated by java . util . logging . logger ? one alternative is to do something like the following :
from the remaining 98 % majority , about 70 % are using an abstraction framework like slf4j or commons logging , with slf4j being the grand winner with 61 % . around 28 % use nothing .
http event collector requires splunk 6 . 3 + . splunk java library supports sending events through java . util . logging , log4j and logback standard loggers . in order to use http event collector it has to be enabled on the server and an application token should be created .
the marklogic java api support reading , writing , and deleting document content and metadata as well as querying documents .
private final static java . util . logging . logger . logger logger = java . util . logging . logger . logger . getlogger ( myclass . class . getname ( ) ) ; private final logger slf4jlogger = loggerfactory . getlogger ( slf4jhello . class ) ; private final static logger log4jlogger = logger . getlogger ( log4jhello . class ) ;
: defines a set of standard logging levels that can be used to control logging output . programs can be configured to output logging for some levels while ignoring output for others .
# we will write to a splunk tcp input using java . util . logging ' s # sockethandler . this line sets it to be the default handler for # all loggers . handlers = java . util . logging . sockethandler config = # set the default logging level for the root logger . level = info # implicitly create a logger called ' splunk . logger ' , set its # level to info , and make it log using the sockethandler . splunk . logger . level = info splunk . logger . handlers = java . util . logging . sockethandler # configure the sockethandler to write to tcp port localhost : 15000 . # note that tcp inputs are * not * the same as splunk ' s management # port . you can find the documentation about how to open tcp # inputs in splunk at urltoken # # you can find the documentation on using a sockethandler at urltoken java . util . logging . sockethandler . level = info urltoken = localhost java . util . logging . sockethandler . port = 15000 # with java 7 , you can set the format of simpleformatter . on java 6 , # you cannot and you will probably want to write a custom formatter # for your system . the syntax of the format string is given at # urltoken # and urltoken # for logging specific behavior . java . util . logging . sockethandler . formatter = simpleformatter java . util . logging . simpleformatter . format =
% 1 $ f % 1 $ r % 4 $ s : % 6 $ s % n
one of the things that is often missed in logging benchmarks is the cost of not logging . in the ideal world , a logging statement for a logger that is not going to log should be completely eliminated from the execution code path . one of the features of a good logging framework is the ability to change logging levels of a running application . in reality we need at least a periodical check for a change in the logger’s level , so we cannot have the logging statement completely eliminated .
if you wish to use logback - classic as the underlying logging framework , all you need to do is to declare
ch . qos . logback : logback - classic
as a dependency in your
one of the interesting factors of java util logging’s default format is that it includes detail of the source class and method . if you want to get the details of the source class and method , prior to java 9 there is one and only one way : create an exception and walk the stack trace . it will be interesting to see if java 9’s new stack walker api can improve performance .
with both frameworks available , you needed to configure both of them since whatever framework you used , there was surely at least one dependency of your project that used the other . apache commons logging is an api bridge that connects itself to supported logging frameworks . libraries should use commons - logging so that the real framework used is the choice of the project , and is not imposed by the dependencies . this is not always the case , so commons logging does not solve the double configuration problem . morevoer , commons logging suffer from some class - loading problems , leading to noclassdeffounderror errors .
logs incoming and outgoing soap requests / responses . soap requests and responses are logged as warn for exceptions and info for all other requests . you can configure your logging framework to accept logs on these parameters .
runs a set of static code analysis rules on some java source code files and generates a list of problems found .
a java geek © 2008 - 2018 v . oops , are you sure this is a git project ? latest posts
' , we talked about wrapping your logging framework du jour and looked at two reasons for doing this : portability to a different framework and simplifying the api . for these reasons , i usually create my own log level enumeration to maintain ownership of the api surface and , in the past , i ' ve followed log4net and nlog ' s lead with just five logging levels * . here ' s how i use them :
often times , a given project will depend on various components which rely on logging apis other than slf4j . it is common to find projects depending on a combination of jcl , java . util . logging , log4j and slf4j . it then becomes desirable to consolidate logging through a single channel . slf4j caters for this common use - case by providing bridging modules for jcl , java . util . logging and log4j . for more details , please refer to the page on bridging legacy apis .
i would prefer to wrap it , but not for the stated reason . if the concern is the ability to swap out for another framework , use java . util . logging or slf ( java . util . logging isn ' t as easy to use as a wrapper , but it is quite doable ) , and swap away . the reason to use ( yet another ) wrapper is to codify in code the appropriate way of logging . generally an application wants a subset , such as all system errors come with an exception , or have specific guidance about when to use the standard logging levels . those decisions can be encapsulated in a few methods creating more consistent logging decisions over a large code base .
another recurring request was to integrate aop in to logging frameworks . and a nice comment came from a student : “i don’t know what to use . why are there so many logging frameworks ? isn’t there a standard ? ” . this perhaps reflects the need for a review and standardization of java . util . logging .
authors of widely - distributed components and libraries may code against the slf4j interface in order to avoid imposing an logging framework on their end - user . thus , the end - user may choose the desired logging framework at deployment time by inserting the corresponding slf4j binding on the classpath , which may be changed later by replacing an existing binding with another on the class path and restarting the application . this approach has proven to be simple and very robust .
to use the splunk logging for java library , you will need to add it and the logging library you have chosen to use to your project , open a tcp input on a splunk instance to write your log events to , configure your logging system , and then use the splunkcimlogevent class to generate well formed log entries .
whenever the subject of logging in java comes up on twitter , you can be sure you’ll be in for a lot of ranting . this is perhaps best summarised by this tweet from dan allen :
applications ( rather than libraries ) may also choose to use commons - logging . while logging - implementation independence is not as important for applications as it is for libraries , using commons - logging does allow the application to change to a different logging implementation without recompiling code .
i ' m currently looking at upgrading the logging mechanism in a medium - to - large - sized java codebase . messages are currently logged using static methods on a debug class , and i have recommended switching from this to something like slf4j or commons - logging .
slf4j is designed to wrap the currently popular ( existing ) logging frameworks . slf4j does not and cannot make claims about future logging frameworks .
2 platform ' s core logging facilities . the central goal of the logging apis is to support maintaining and servicing software at customer sites .
to use a different framework than log4j , remove the slf4j - log4j12 - v . v . v . jar from your classpath and fetch a different one from urltoken .
for a beginner it might be confusing and if not taught right , you’ll most likely use system . out . print . as with a lot of other java frameworks , logging frameworks exist in order to fill a gap in java’s core . that’s how we end up with a couple of different choices , which i can imagine for a newcomer is not easy find the right tree in the woods of logging frameworks .
if you are developing a microservice , or some other application where you have control over the execution environment , you are probably responsible for selecting the logging framework . there may be cases where you decide to defer picking one by using a logging shim , but you are still going to have to make a choice eventually .
or you can enable asynchronous logging by setting the system property log4jcontextselector to org . apache . logging . log4j . core . async . asyncloggercontextselector .
all authentication events ( logging in , logging out , failed logins , etc . ) that allow to detect brute force and guessing attacks too .
the java logging apis do not provide any direct support for unique message ids . those applications or subsystems requiring unique message ids should define their own conventions and include the unique ids in the message strings as appropriate .
if the framework or language has a structured exception handler ( i . e . try { } catch { } ) , it should be used in preference to functional error handling .
is a very different implementation which is minimized and optimized for spring ' s purposes , detecting log4j 2 . x and slf4j 1 . 7 in the framework classpath and falling back to
all the logging frameworks discussed in the article share the notion of loggers , appenders and layouts . enabling logging inside the project follows three common steps :
- dorg . apache . commons . logging . log = org . apache . commons . logging . impl . simplelog - dorg . apache . commons . logging . simplelog . showdatetime = true - dorg . apache . commons . logging . simplelog . log . org . apache . http = debug
. this change implies that slf4j requires jdk 1 . 5 or later . under the hood the java compiler transforms the varargs part in methods into
handlers = com . splunk . logging . httpeventcollectorlogginghandler com . splunk . logging . httpeventcollectorlogginghandler . url = https : / / splunk - server : 8088 com . splunk . logging . httpeventcollectorlogginghandler . token = < token - guid >
there is one exception to this . if your code is meant to be deployed into many possible app servers seemlessly , you do have to make sure that your logging choice doesn ' t risk conflicting with potentially older or newer versions of whatever the framework is using .
< ! - - adds the log4j framework - - > < dependency > < groupid > log4j < / groupid > < artifactid > log4j < / artifactid > < version > 1 . 2 . 16 < / version > < / dependency > < ! - - make slf4j use jdk logging as the logging framework - - > < dependency > < groupid > org . slf4j < / groupid > < artifactid > slf4j - jdk14 < / artifactid > < version > 1 . 7 . 12 < / version > < / dependency >
but given that it is present in most major framework , i am guessing it is useful for something ? so . . . what is trace for , and what distinguishes it from debug ?
java . util . logging . filehandler . limit specifies an approximate maximum amount to write ( in bytes ) to any one file . if this is zero , then there is no limit . ( defaults to no limit ) .
to switch logging frameworks , just replace slf4j bindings on your class path . for example , to switch from java . util . logging to log4j , just replace slf4j - jdk14 - 1 . 8 . 0 - beta2 . jar with slf4j - log4j12 - 1 . 8 . 0 - beta2 . jar .
applications make logging calls on logger objects . loggers are organized in a hierarchical namespace and child loggers may inherit some logging properties from their parents in the namespace .
a new security permission loggingpermission is defined to control updates to the logging configuration .
- dorg . apache . commons . logging . log = org . apache . commons . logging . impl . simplelog - dorg . apache . commons . logging . simplelog . showdatetime = true - dorg . apache . commons . logging . simplelog . log . org . apache . http . impl . conn = debug
would conflict with commons - logging api in jcl - over - slf4j . jar
all of the tcp appenders we show config files for ( sockethandler for java . util . logging , socketappender for log4j 2 , and the tcpappender provided with this library for logback ) will attempt to reconnect in case of dropped connections .
jdk 1 . 4 logging is a standard and does not raise concurrent versions problems . but it lacks so many features , it cannot be used without redeveloping some such as a database adapter and such . too bad… but it does not answers the question : which framework to use ?
in addition there is a level off that can be used to turn off logging , and a level all that can be used to enable logging of all messages .
note that commons - logging does not attempt to initialise or terminate the underlying logging implementation that is used at runtime ; that is the responsibility of the application . however many popular logging implementations do automatically initialise themselves ; in this case an application may be able to avoid containing any code that is specific to the logging implementation used .
- dorg . apache . commons . logging . log = org . apache . commons . logging . impl . simplelog - dorg . apache . commons . logging . simplelog . showdatetime = true - dorg . apache . commons . logging . simplelog . log . org . apache . http = debug - dorg . apache . commons . logging . simplelog . log . org . apache . http . wire = error
today we are starting a log4j tutorial series under ' log4j configuration in spring ' . we will cover topics on ' log4j in java ' and come to know what is log4j in java ? ' . here we will get a dive into basics of log4j and configuration of log4j with spring under three parts . these parts are
if one thing came clear from this open question , it is that the respondents find that there are too many ‘standards’ and that there should be only one . namely : replace jdk logging with slf4j as a real java spec and stop the changes !
slf4j offers a jar for each logging framework : they mimic its api but reroute the calls to the slf4j api ( which in turn uses the real framework ) . a word of warning : you could run into a cycle so beware to not have the bridging library along the implementation library in your classpath . for example , if you use the log4j bridge , each log4j api call will be rerouted to slf4j . but if the slf4j log4j implementation is present , it will be routed back to log4j then again , and again .
< ! - - adds the log4j framework - - > < dependency > < groupid > log4j < / groupid > < artifactid > log4j < / artifactid > < version > 1 . 2 . 16 < / version > < / dependency > < ! - - make slf4j use log4j as the logging framework - - > < dependency > < groupid > org . slf4j < / groupid > < artifactid > slf4j - log4j12 < / artifactid > < version > 1 . 7 . 7 < / version > < / dependency >
there is a global logmanager object that keeps track of global logging information . this includes :
this seems like overkill to me , as slf4j is already abstracting the concrete logging implementation .
debug level logging can usually be on for a longer period without making the app unusable .
@ andy256 - in my experience , trace level logging disrupts that sort of stuff too .
. the logging information used by field service engineers may be considerably more complex and verbose than that required by system administrators . typically such information will require extra logging within particular subsystems .
in case you wish to migrate your java source files to slf4j , consider our migrator tool which can migrate your project to use the slf4j api in just a few minutes .
mvn exec : java - dexec . mainclass =
net . openhft . chronicle . logger . tools . chronicat
- dexec . args =
…
- - -
the logback - core module lays the groundwork for the other two modules . the logback - classic module can be assimilated to a significantly improved version of log4j . moreover , logback - classic natively implements the slf4j api so that you can readily switch back and forth between logback and other logging frameworks such as log4j or java . util . logging ( jul ) .
an event message format could be configured for http event appender in logging framework configuration . it could have one of the two possible values - text , json . it is an optional property with default value as ' text ' . message format ' json ' is used where the event message could be in json format .
- dorg . apache . commons . logging . log = org . apache . commons . logging . impl . simplelog - dorg . apache . commons . logging . simplelog . showdatetime = true - dorg . apache . commons . logging . simplelog . log . org . apache . http . impl . conn = debug - dorg . apache . commons . logging . simplelog . log . org . apache . http . impl . client = debug - dorg . apache . commons . logging . simplelog . log . org . apache . http . client = debug
the goal of this package ( sometimes referred to as
the pojo facade
is to simplify working with custom plain old java objects ( pojos ) without hassling with persistence details .
another aspect of logging benchmarks , is selective configuration . each of the different logging frameworks come with their own different default output configuration . if we do not configure all the loggers to use the same output format , we will not be comparing like with like . conversely , some logging frameworks may have special case optimisations that work for specific logging formats which could distort the results .
it will enable logging for com . baeldung . log4j package and your output will look like :
logback uses slf4j as native api for its functionality . following is the example using logback logging :
a set of logging control properties read from the configuration file . see section 1 . 8 .
the principal security requirement is that untrusted code should not be able to change the logging configuration . specifically , if the logging configuration has been set up to log a particular category of information to a particular handler , then untrusted code should not be able to prevent or disrupt that logging .
it seems that a logging facade or a third party library are the only completely safe options .
if you want to use jdk logging , add the following to your pom . xml file .
configure your logging system . here are simple example configurations for each of the three systems . the log4j2 . xml and logback . xml files should be put somewhere in the classpath of your program . urltoken should be specified to your program by passing the following to the java executable :
the real challenge with logging in java is in configuring these frameworks for your use - case . it took a lot of digging , research and experimentation to get what i believe to be a performant and fair set of configurations to use as a basis for comparison . i am quite sure that some of the developers of logging frameworks will take issue with some aspects of my configurations .
commons logging comes with a basic logger called simplelog . this logger writes all logged messages to system . err . the following examples show how to configure commons logging via system properties to use simplelog . it is strongly recommended to configure commons logging system properties through jvm process arguments at the start up .
problem diagnosis by developers . the logging apis may also be used to help debug an application under development . this may include logging information generated by the target application as well as logging information generated by lower - level libraries . note however that while this use is perfectly reasonable , the logging apis are not intended to replace the normal debugging and profiling tools that may already exist in the development environment .
log4j would be the framework of choice ( and is for most ) but it is no longer developed . version 1 . 2 is the reference , version 1 . 3 is abandoned and version 2 . 0 is still in its early stage .
if you ' re thinking of switching logging frameworks in the future , it may be worthwhile to add an extra layer to where you can switch out the logger . otherwise , if they provide everything that you will possibly need ( using your crystal ball , of course ) then it is probably ok to have a hard dependency on that framework .
there are two different styles of logging methods , to meet the needs of different communities of users .
here ' s a small program that sets up its own logging handler and ignores the global configuration .
the location of the logging message , i . e . name of the source file + line number
- djava . util . logging . config . file = / path / to / jdklogging . properties
errormanager objects can be attached to handlers to process any error that occurs on a handler during logging .
the second most popular is log . debug (
hey , we ' re adding { 0 } to the database now ! it has id { 1 }
, entity , entity . getid ( ) ) , which is a good thing since it leverages the capabilities of the logging framework , such as with most slf4j implementations where it will not create the actual logged string unless the logging level is enabled to save your applications some processor instructions .
as with most java platform apis , the logging apis are designed for use inside a single address space . all calls are intended to be local . however , it is expected that some handlers will want to forward their output to other systems . there are a variety of ways of doing this :
and even in this case , i hope you are using java 6 or higher , since any compiler before that will not convert string concatenations to a stringbuffer version and it would impact runtime performance .
due to the way that classes are loaded by the jvm , the framework binding will be verified automatically very early on . if slf4j cannot find a binding on the class path it will emit a single warning message and default to no - operation implementation .
today most programs require the logging of large amounts of data , especially in trading systems where this is a regulatory requirement . loggers can affect your system performance , therefore logging is sometimes kept to a minimum . with chronicle logger we aim to minimize logging overhead , freeing your system to focus on the business logic .
furthermore , 23 % of respondents wrap their logging statements with an “if” where they check if the called logging level is enabled or not . but when it comes to actually enabling these levels , it’s another story .
a minimal incarnation of apache commons logging ' s logfactory api , providing just the common log lookup methods .
besides xml or json , you can also get search results as a java data structure by using searchhandle . this approach is often the most convenient way to manipulate search results as demonstrated in the following example :
logback’s asynchronous appender is not recommended for multi - threaded logging due to an unresolved bug in the current implementation .
the following code adds error handling and logging to the dblogin and logout methods in the code from authentication section .
continuing our recent logging theme , i want to talk about the different logging levels and some guidance on how to use them . most logging frameworks ( entlib , log4net , nlog etc ) support some kind of logging level or severity , where each individual log entry is marked at a certain level such as
warning
,
error
or
information
. not only is this great for ranking the importance of a particular entry , it can also be used to control the amount of logging making its way through to your log repository of choice .
: provides fine - grained control over what gets logged , beyond the control provided by log levels . the logging apis support a general - purpose filter mechanism that allows application code to attach arbitrary filters to control logging output .
the majority of people ( 70 % ) write logging statements in their application to print out informational and error statements . only 1 % claims to only write logging calls for only errors while another 10 % is in love with logging and would try to log as much as they can . the remainders aren’t really sure , they do other things .
always use the logging level that provides the smallest level of detail that is sufficient . this reduces as much as possible the amount of logging data that you have to sift through . that said , there are no hard and fast rules for which logging level to use in any given scenario . use the one that is most helpful to you .