Develop Reference

is it possible to avoid error information in text.INFO file of log4j properties?

I am using log4j properties to capture the logs.i wants to remove error info from INFO file.
**
INFO
** file is below:
5:39:02,068 INFO BluSyncLauncher:156 - Application started
05:39:02,080 INFO BluSyncLauncher:586 - Loading UI
05:39:02,263 INFO BackupCrawlDAOImpl:470 - sqlExeception in CREATE_ACTIVITY_TABLEjava.sql.SQLException: [SQLITE_ERROR] SQL error or missing database (duplicate column name: IsFolder)
05:39:02,264 **
ERROR
** BackupActivityHistoryDAOImpl:706 - sqlExeception in CREATE_ACTIVITY_TABLEjava.sql.SQLException: [SQLITE_ERROR] SQL error or missing database (duplicate column name: restartid)
05:39:03,803 INFO BluSyncLauncher:533 - Started crawl (backup)
05:39:03,827 INFO BluSyncLauncher:543 - Starting Activity Timer
05:39:03,860 INFO BluSyncLauncher:557 - Load SystemTrayUI
05:39:10,612 **
ERROR
** BackupPolicyDAOImpl:280 - SQLException while inserting backup policy details
java.sql.SQLException: [SQLITE_CONSTRAINT] Abort due to constraint violation (BACKUP_POLICY.policyGroupName may not be NULL)
at org.sqlite.DB.newSQLException(DB.java:383)
at org.sqlite.DB.newSQLException(DB.java:387)
at org.sqlite.DB.execute(DB.java:342)
at org.sqlite.PrepStmt.execute(PrepStmt.java:65)
at com.parablu.epa.common.dao.BackupPolicyDAOImpl.insertBackupPolicyDetailsToTable(BackupPolicyDAOImpl.java:273)
at com.parablu.epa.common.service.settings.PolicyManagementServerHelper.createGroupPolicyAndChildDetails(PolicyManagementServerHelper.java:306)
at com.parablu.epa.common.service.settings.PolicyManagementServerHelper.loadBackupPolicyElement(PolicyManagementServerHelper.java:245)
at com.parablu.epa.service.backup.LinuxCheckBackupPolicy.checkGroupPolicy(LinuxCheckBackupPolicy.java:140)
at com.parablu.epa.service.alarm.LinuxPolicyRefreshHelper$1.run(LinuxPolicyRefreshHelper.java:55)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)

Loggers may be assigned levels. The set of possible levels, that is:
TRACE,
DEBUG,
INFO,
WARN,
ERROR and
FATAL
are defined in the org.apache.log4j.Level class. Although we do not encourage you to do so,
you may define your own levels by sub-classing the Level class.
Level Inheritance
A logging request is said to be enabled if its level is higher than or equal to the level of its logger. Otherwise, the request is said to be disabled. A logger without an assigned level will inherit one from the hierarchy. This rule is summarized below.
Basic Selection Rule
A log request of level p in a logger with (either assigned or
inherited, whichever is appropriate) level q, is enabled if p >= q.
UPDATE:
In Log4j2 version 2.0.2
If you wish to change the root logger level, do something like this :
LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
Configuration config = ctx.getConfiguration();
LoggerConfig loggerConfig = config.getLoggerConfig(LogManager.ROOT_LOGGER_NAME);
loggerConfig.setLevel(level);
ctx.updateLoggers(); // This causes all Loggers to refetch information from their LoggerConfig.

I get some information from log4j filter
and read the log4j source code. I found it is possible.
Do like this:
appender.File.type=File
appender.File.name=infolog
appender.File.layout.type=PatternLayout
appender.File.layout.pattern=%d %p %C{1.} [%t] %m%n
appender.File.filename=${infologfilename}
#here! add filter named star, type is ThresholdFilter
appender.File.filter.star.type=ThresholdFilter
#level you want to filter
appender.File.filter.star.level=info
#if mathched the level, the log higher then the level will not output
appender.File.filter.star.onMatch=DENY
#if mismathed,output
appender.File.filter.star.onMisMatch=ACCEPT
May be it can help you.
I suggest you to use xml configuration,easy to read and edit.

Write multiple log4j files with different info

The API I am working on cannot be connected to a database, but need to log events that are happening in the API. To do this I was thinking on using log4j to create log file with API event information.
The problem is that all log entries end up in both logs, and not separated.
Requirements I am need to fulfill
Multiple log files with certain information inside
Backup log files live indefinitely
Log4j properties file
log4j.rootLogger=QuietAppender, LoudAppender, FirstLog, SecondLog, TRACE
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - <%m>%n
# setup A1
log4j.appender.QuietAppender=org.apache.log4j.RollingFileAppender
log4j.appender.QuietAppender.Threshold=INFO
log4j.appender.QuietAppender.File=${wls.logs-path}/test-api/test-api-info.log
log4j.appender.QuietAppender.MaxFileSize=512KB
log4j.appender.QuietAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.QuietAppender.layout.ConversionPattern=%d %p [%c] - %m%n
# Keep three backup files.
log4j.appender.QuietAppender.MaxBackupIndex=100
# Pattern to output: date priority [category] - message
log4j.appender.QuietAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.QuietAppender.layout.ConversionPattern=%d %p [%c] - %m%n
# setup A2
log4j.appender.LoudAppender=org.apache.log4j.RollingFileAppender
log4j.appender.LoudAppender.Threshold=DEBUG
log4j.appender.LoudAppender.File=${wls.logs-path}/test-api/test-api-debug.log
log4j.appender.LoudAppender.MaxFileSize=512KB
# Keep three backup files.
log4j.appender.LoudAppender.MaxBackupIndex=3
# Pattern to output: date priority [category] - message
log4j.appender.LoudAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.LoudAppender.layout.ConversionPattern=%d %p [%c] - %m%n
# setup FirstLog
log4j.appender.FirstLog=org.apache.log4j.RollingFileAppender
log4j.appender.FirstLog.Threshold=INFO
log4j.appender.FirstLog.File=${wls.logs-path}/test-api/first-info.log
log4j.appender.FirstLog.MaxFileSize=10240kB
log4j.appender.FirstLog.MaxBackupIndex=99999
log4j.appender.FirstLog.layout=org.apache.log4j.PatternLayout
log4j.appender.FirstLog.layout.ConversionPattern=%d %p [%c] - %m%n
# setup SecondLog
log4j.appender.SecondLog=org.apache.log4j.RollingFileAppender
log4j.appender.SecondLog.Threshold=INFO
log4j.appender.SecondLog.File=${wls.logs-path}/test-api/second-info.log
log4j.appender.SecondLog.MaxFileSize=10240kB
log4j.appender.SecondLog.MaxBackupIndex=99999
log4j.appender.SecondLog.layout=org.apache.log4j.PatternLayout
log4j.appender.SecondLog.layout.ConversionPattern=%d %p [%c] - %m%n
Java Class
private static final Logger logkp = Logger.getLogger("FirstLog");
private static final Logger logda = Logger.getLogger("SecondLog");
logkp.info(sb.toString());
logda.info(sb.toString());
Current Results
2015-05-27 10:27:46,175 INFO [SecondLog] - 12645,APIServer1,0,000bdc5000000100011055042d0114a6
2015-05-27 10:27:46,583 INFO [FirstLog] - APIServer1,Caller,test-Version-1.0,certValue,1
2015-05-27 10:28:22,458 INFO [SecondLog] - 12645,APIServer1,0,000bdc5000000100011055042d0114a6
2015-05-27 10:28:22,793 INFO [FirstLog] - APIServer1,Caller,test-Version-1.0,certValue,1
2015-05-27 10:28:25,203 INFO [SecondLog] - 12645,APIServer1,0,000bdc5000000100011055042d0114a6
2015-05-27 10:28:25,528 INFO [FirstLog] - APIServer1,Caller,test-Version-1.0,certValue,1
2015-05-27 10:28:26,686 INFO [SecondLog] - 12645,APIServer1,0,000bdc5000000100011055042d0114a6

I'm not 100% sure about this, because it's been a while that I was using log4j and we used to write the configuration in xml, but I think you have to create loggers like this:
log4j.rootLogger=QuietAppender, LoudAppender, TRACE
log4j.logger.FirstLogger = FirstLog, INFO
log4j.additivity.FirstLogger = false
log4j.logger.SecondLogger = SecondLog, INFO
log4j.additivity.SecondLogger = false
... // then configure appenders as you did
To get the outputs you want. Setting the additivity to false "cuts" the connection to the rootLogger. It is set to true by default and will cause all logmessages to be appended to the logger and to all ancestors of the logger. Setting it to false will change that.
If your API has its own namespace - let's say "my.own.API" then you could also create an API-Logger like this:
log4j.logger.my.own.API = MyAPIAppender, INFO
log4j.additivity.my.own.API = false
And create loggers like this:
package my.own.API
public class MyAPIClass{
private static Logger apiLog = Logger.getLogger(MyAPIClass.class);
// ...
}

How to create Custom Log and Debug Log Separately using log4j

I want to create 2 types of log 1 Debug log which will create all log another I want to create activity log I mean each method how much time took to execute or any specific info,
I am using below log4j property file-
please correct me, its logging all messages in only one file,in java I have instantiated both log object, kindly don't send any pointers or just Google because I have tried since last 2 days all options as described in Google,
Thanks in advance for your kind support,
log4j.rootLogger=debugLog,reportsLog
log4j.appender.debugLog=org.apache.log4j.FileAppender
log4j.appender.debugLog.File=logs/debug.log
log4j.appender.debugLog.layout=org.apache.log4j.PatternLayout
log4j.appender.debugLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n
log4j.appender.reportsLog=org.apache.log4j.FileAppender
log4j.appender.reportsLog.File=logs/reports.log
log4j.appender.reportsLog.layout=org.apache.log4j.PatternLayout
log4j.appender.reportsLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n
log4j.category.debugLogger=INFO, debugLog
log4j.additivity.debugLogger=false
log4j.category.reportsLogger=DEBUG, reportsLog
log4j.additivity.reportsLogger=false

Below log4j.properties file will configure the logger to log the messages with debug level to the logs/debug.log file. Messages with level INFO...FATAL are logged to logs/reports.log.
log4j.rootLogger=DEBUG, debugLog, reportsLog
log4j.appender.debugLog=org.apache.log4j.FileAppender
log4j.appender.debugLog.File=logs/debug.log
log4j.appender.debugLog.layout=org.apache.log4j.PatternLayout
log4j.appender.debugLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n
log4j.appender.debugLog.filter.f1=org.apache.log4j.varia.LevelRangeFilter
log4j.appender.debugLog.filter.f1.LevelMax=DEBUG
log4j.appender.debugLog.filter.f1.LevelMin=DEBUG
log4j.appender.reportsLog=org.apache.log4j.FileAppender
log4j.appender.reportsLog.File=logs/reports.log
log4j.appender.reportsLog.layout=org.apache.log4j.PatternLayout
log4j.appender.reportsLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n
log4j.appender.reportsLog.filter.f1=org.apache.log4j.varia.LevelRangeFilter
log4j.appender.reportsLog.filter.f1.LevelMax=FATAL
log4j.appender.reportsLog.filter.f1.LevelMin=INFO
log4j.category.debugLogger=DEBUG, debugLog
log4j.additivity.debugLogger=false
log4j.category.reportsLogger=INFO, reportsLog
log4j.additivity.reportsLogger=false

Log4j logs decreases application performance?

Does logging decreases application performance?
and how to restrict display-tags logs to be printed in log files?
eg. my log file has below logs
[2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1)
[2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1)
[2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1)
[2012-06-20 15:52:06,290] org.displaytag.tags.TableTag isFirstIteration 684 - [data] first iteration=true (row number=1)
why the above is in log file?
log.properties file
# Log4j configuration file.
log4j.rootCategory=DEBUG, A1
# Available levels are DEBUG, INFO, WARN, ERROR, FATAL
#
# A1 is a ConsoleAppender
#
log4j.appender.A1 = org.apache.log4j.RollingFileAppender
log4j.appender.A1.File = C:/LogInfo/logfile.log
log4j.appender.A1.MaxFileSize = 100MB
log4j.appender.A1.MaxBackupIndex=50
log4j.appender.A1.layout = org.apache.log4j.PatternLayout
log4j.appender.A1.append = true
log4j.appender.A1.layout.ConversionPattern = [%d] %C %M %L - %m%n
log4j.appender.A1.Threshold = DEBUG
how to stop (org.displaytag.tags.TableTag) these kind of logs to be printed in log files

Does logging decreases application performance?
Yes. How much it does depends on a number of factors; see below.
and how to restrict display-tags logs to be printed in log files?
By changing the ConversionPattern in the logging properties
why the above is in log file?
Because:
somewhere in the code is a call to a Logger method (probably debug(String)) with that message, and
your logging properties set the logging Threshold to DEBUG for the appender.
To improve performance:
change the ConversionPattern to use less expensive date/time formatting, and (more importantly) avoid 'C', 'F', 'L' and 'M' because they are particularly expensive.
change the logging Threshold to INFO or WARNING or ERROR to reduce the amount of logging,
put the Logger.debug(...) call inside an if statement that checks that debug logging is enabled. This saves the cost of assembling the log message in cases where it won't be needed; see In log4j, does checking isDebugEnabled before logging improve performance?.
with log4j version 2 (log4j2), there are overloads that on the logging methods that take a format and parameters. These reduce the overhead when a logging at a level that is disabled.
look also at logback and log4j 2.0.
You can also throttle logging at the Logger level ... as described in the log4j documentation. In fact, the documentation answers most of the questions that you asked, and has a lot of detail on the topics of logging performance and logging configuration.

Short answer: yes, it decreases application performance as it uses some CPU cycles and other resources (memory, etc).
See also this question : log4j performance

Logging can be 30% of you cpu time or more. In terms of jitter, it as large (and more often) than your GC delays.
A simple way to reduce overhead is to use the Pattern to turn off where you are logging each message from. In your case this is %C %M and %L as it has to take a stack trace (of the entier stack) to get this information.

Yes they do. That's why you should only log an error or something that must absolutely be logged. You can also log information helpful for debugging in the debug channel so it won't affect production performance.

how about?
log4j.category.org.displaytag.tags.TableTag=ERROR, A1

You can restrict junk logs like this.
Set the root logger as INFO so that unnecessary debug logs won't come and fill up your log file.
log4j.rootCategory=INFO, A1
If you want specific class or package to give out DEBUG logs you can do it like this.
log4j.logger.org.hibernate.event.def.DefaultLoadEventListener=DEBUG,A1
The above will print DEBUG level logs from the class DefaultLoadEventListener in your log file along with other INFO level logs.

Log4j logging info messages without logging warn messages

I'm trying to log certain info messages onto a file but as soon as I run the application both warn and info messages are logged. Now, from what I've read from this site, you cannot log one without logging the other. Has anyone tried this before? If so, how did your properties file look like?
My properties file looks like this:
***** Set root logger level to INFO and its two appenders to stdout and R.
log4j.rootLogger=INFO, stdout, R
# ***** stdout is set to be a ConsoleAppender.
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
# ***** stdout uses PatternLayout.
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
# ***** Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%5p [%M has started] (%F:%L) - %m%n
/
# ***** R is set to be a RollingFileAppender.
log4j.appender.R=org.apache.log4j.DailyRollingFileAppender
log4j.appender.R.DatePattern='.'yyyy-MM-dd-HH
log4j.appender.R.File="folder where log will be saved"
log4j.appender.R.layout.ConversionPattern=%5p [%m has started] %c{2}.[%x] (%F:%L) %d{yyyy-MM-dd HH:mm:ss} - %m%n
# ***** R uses PatternLayout.
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%5p [%m has started] %c{2}.[%x] (%F:%L) %d{yyyy-MM-dd HH:mm:ss} - %m%n

AFAIK there's no standard way to suppress higher log levels than those you are interested in.
However, you might be able to use a custom appender to do that.
It might look similar to this:
public class MyAppender extends AppenderSkeleton {
protected void append(LoggingEvent event) {
if( event.getLevel() == Level.INFO ) {
//append here, maybe call a nested appender
}
}
}

The log level WARN is higher than INFO, and the logging configuration defines the minimum threshold level to be logged by the appender. So, all messages higher than that level will also be logged.
Hence, the WARN messages are expected. And I don't think you can configure it to the way you want.

If the WARN messages that should not be printed come from a different package than the INFO messages, then you can define different log levels for these packages. The first can specify level ERROR and the second INFO
it should look something like this:
log4j.logger.com.test.something=ERROR
log4j.logger.com.other.package=INFO
cheers

Why do you want to filter the WARN level? As peshkira said, you could use two different loggers for splitting/filtering your log output, or you could use tools like grep for filtering (offline) or you could simply remove the WARN logs from your code if your don't need them anyway.

As far as I understand, advanced filters like LevelMatchFilter and LevelRangeFilter can do the trick for you.
Thing worth keeping in mind though is that using these may require xml config instead of properties: Can't set LevelRangeFilter for log4j