I am trying to run the 2newsgroup classification example in Mahout. I have set MAHOUT_LOCAL=true, the classifier doesn't display the Confusion matrix and gives the following warnings :
ok. You chose 1 and we'll use cnaivebayes
creating work directory at /tmp/mahout-work-cloudera
+ echo 'Preparing 20newsgroups data'
Preparing 20newsgroups data
+ rm -rf /tmp/mahout-work-cloudera/20news-all
+ mkdir /tmp/mahout-work-cloudera/20news-all
+ cp -R /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/alt.atheism /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.graphics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.os.ms-windows.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.sys.ibm.pc.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.sys.mac.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.windows.x /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/misc.forsale /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.autos /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.motorcycles /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.sport.baseball /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.sport.hockey /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.crypt /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.electronics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.med /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.space /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/soc.religion.christian /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.guns /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.mideast /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.religion.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/alt.atheism /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.graphics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.os.ms-windows.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.sys.ibm.pc.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.sys.mac.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.windows.x /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/misc.forsale /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.autos /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.motorcycles /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.sport.baseball /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.sport.hockey /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.crypt /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.electronics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.med /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.space /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/soc.religion.christian /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.guns /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.mideast /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.religion.misc /tmp/mahout-work-cloudera/20news-all
+ '[' '' '!=' '' ']'
+ echo 'Creating sequence files from 20newsgroups data'
Creating sequence files from 20newsgroups data
+ ./bin/mahout seqdirectory -i /tmp/mahout-work-cloudera/20news-all -o /tmp/mahout-work-cloudera/20news-seq -ow
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.common.AbstractJob).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
+ echo 'Converting sequence files to vectors'
Converting sequence files to vectors
+ ./bin/mahout seq2sparse -i /tmp/mahout-work-cloudera/20news-seq -o /tmp/mahout-work-cloudera/20news-vectors -lnorm -nv -wt tfidf
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.vectorizer.SparseVectorsFromSequenceFiles).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
+ echo 'Creating training and holdout set with a random 80-20 split of the generated vector dataset'
Creating training and holdout set with a random 80-20 split of the generated vector dataset
+ ./bin/mahout split -i /tmp/mahout-work-cloudera/20news-vectors/tfidf-vectors --trainingOutput /tmp/mahout-work-cloudera/20news-train-vectors --testOutput /tmp/mahout-work-cloudera/20news-test-vectors --randomSelectionPct 40 --overwrite --sequenceFiles -xm sequential
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.driver.MahoutDriver).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
+ echo 'Training Naive Bayes model'
Training Naive Bayes model
+ ./bin/mahout trainnb -i /tmp/mahout-work-cloudera/20news-train-vectors -el -o /tmp/mahout-work-cloudera/model -li /tmp/mahout-work-cloudera/labelindex -ow -c
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.driver.MahoutDriver).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
+ echo 'Self testing on training set'
Self testing on training set
+ ./bin/mahout testnb -i /tmp/mahout-work-cloudera/20news-train-vectors -m /tmp/mahout-work-cloudera/model -l /tmp/mahout-work-cloudera/labelindex -ow -o /tmp/mahout-work-cloudera/20news-testing -c
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.driver.MahoutDriver).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
+ echo 'Testing on holdout set'
Testing on holdout set
+ ./bin/mahout testnb -i /tmp/mahout-work-cloudera/20news-test-vectors -m /tmp/mahout-work-cloudera/model -l /tmp/mahout-work-cloudera/labelindex -ow -o /tmp/mahout-work-cloudera/20news-testing -c
MAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.
MAHOUT_LOCAL is set, running locally
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/mahout-examples-1.0-SNAPSHOT-job.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/cloudera/mahout-master/examples/target/dependency/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.mahout.driver.MahoutDriver).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Please give me any solution Thanks.
After lots of hour searching i found this solution :
Create log4j.properties file
This is the main properties file having all runtime configuration used by log4j. This file will have appenders information, log level information and output file names for file appenders.
log4j.rootLogger=DEBUG,consoleAppender, fileAppender
log4j.appender.consoleAppender=org.apache.log4j.ConsoleAppender
log4j.appender.consoleAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.consoleAppender.layout.ConversionPattern=[%t] %-5p %c %x - %m%n
log4j.appender.fileAppender=org.apache.log4j.RollingFileAppender
log4j.appender.fileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.fileAppender.layout.ConversionPattern=[%t] %-5p %c %x - %m%n
log4j.appender.fileAppender.File=demoApplication.log
This error was due to "log4j.properties" file missing you can find more info about this on : http://www.tutorialspoint.com/log4j/log4j_configuration.htm
来源：https://stackoverflow.com/questions/27261337/how-to-solve-log4jwarn-no-appenders-could-be-found-for-logger-error-on-twenty