I was kind curious about the warning when I start android studio 2.0 and always got this message in my terminal:
log4j:WARN No appenders could be found for logger (io.netty.util.internal.logging.InternalLoggerFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
I have visited the suggested site and from what I understand the configuration files log4j.properties and log4j.xml are missing so I tried to find the file in the root directory and I could not found them this is the screenshot :
My Questions are :
How to resolve this issue so I will not see the warning message again?
Could somebody explain what is log4j for in android studio?
any help and useful information would be appreciated thanks.
it's no critical error. Log4j is a logging framework to log output. If you don't have a configuration file, nothing is logged. You can add them manually if you want.
Related
I am using web-based application along with Log4J API for logging purpose.
In Log4J, I am using DailyRollingFileAppender to create a new log file for logging on each day.
here is my log4j properties file configuration
log4j.logger.org.apache.cxf=ERROR
log4j.rootLogger=INFO, jtiServiceAppender
log4j.appender.jtiServiceAppender=org.apache.log4j.DailyRollingFileAppender
log4j.appender.jtiServiceAppender.File=${catalina.home}/logs/jti/ilume-mw${logfilename}-app.log
log4j.appender.jtiServiceAppender.DatePattern='.'yyyy-MM-dd
log4j.appender.jtiServiceAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.jtiServiceAppender.layout.ConversionPattern=%d{dd.MM.yyyy HH\:mm\:ss} %-5p %t [%C{1}]\: %m%n
Problem:
In my case, the log files are not created for each day. For the same when I checked my tomcat server log I have observed that I am getting an error as
log4j:ERROR Failed to rename [D:\ilume-mwtmp0-app.log] to
[D:\ilume-mwtmp0-app.log.2019-07-09].
I have also referred the below link however still, I did not find a proper solution to my case.
Link : enter link description here
Any help or suggestion to solve this logging problem will be highly appreciated as it's been a couple of days and I am still not able to get any proper solution to this problem.
When adding appender-ref in logger tag, it throws renaming error. When adding appender-ref in root tag, it never throws that error.
Above is from below link. It seems same error and might help.
log4j:ERROR Failed to rename
Other than above, please check if there is permission issue at the directory where file needs to be renamed.
Why is stdout file of a job container in hadoop is always of size 0.
On java
import org.apache.log4j.Logger;
static final Logger MAPLOGGER= Logger.getLogger(MyMap.class.getName());
MAPLOGGER.warn("key is :"+key);
after running jar, 3 files are generated
stderr, stdout,syslog
stderr contains
log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.impl.MetricsSystemImpl).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
where exactly MAPLOGGER.warn("key is :"+key); writes the log?.
It doesn't write it anywhere right now, because you have not set up log4j.
From the link in the WARN message:
"Why do I see a warning about "No appenders found for logger" and "Please configure log4j properly"?
This occurs when the default configuration files log4j.properties and log4j.xml can not be found and the application performs no explicit configuration. log4j uses Thread.getContextClassLoader().getResource() to locate the default configuration files and does not directly check the file system. Knowing the appropriate location to place log4j.properties or log4j.xml requires understanding the search strategy of the class loader in use. log4j does not provide a default configuration since output to the console or to the file system may be prohibited in some environments."
So you need to set up the log4j engine, and give it to Java overall, or explicitly declare their location in the application.
i work with log4j and now that i want to use it i get this:
log4j:WARN No appenders could be found for logger (xmlModul.XmlLoader).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
but the website didnt help me and i asked this some time ago but i simply cant figure out how and where to set the class path.
but now that the deadline draws near i'm frightened that i cant finish it.
I really need a step-by-step solution.
thank you for your help.
Edit:
i know that the file has to be in the directory but no matter where i put it it wont find the log4j.properties file
Whenever I debug my code in Netbeans this appears:
log4j:WARN No appenders could be found for logger (org.apache.pdfbox.pdfparser.PDFObjectStreamParser).
log4j:WARN Please initialize the log4j system properly.
Why is this? Is this important?
Why is this?
The reason why you see this message is that your log4j configuration file(i.e. log4j.xml or log4j.properties) is NOT found in the classpath. Placing the log4j configuration file in the applications classpath should solve the issue.
is this important?
Depends on requirement, if you want messages logged to a file with defined levels, then yes you need to fix this warning. Otherwise you may ignore.
For setting Log4j in runtime, do this:
java -Dlog4j.configuration=file:///D:/crawler4j-3.5/log4j.properties -jar newCrawlerV0.1.jar
I get the following:
log4j:WARN No appenders could be found for logger (org.test.Books).
log4j:WARN Please initialize the log4j system properly.
I do not want to print these messages, regardless to whether if my log4j configuration is correct or not.
To turn off the warnings try:
Logger.getRootLogger().setLevel(Level.OFF);
And as said in the comment it might be better using the log4j.xml here is a nice link on its format and a few examples too: http://wiki.apache.org/logging-log4j/Log4jXmlFormat
Reference:
How to turn off log4j warnings?