Log4j configuration is a difficult topic, because there's so many ways
to do it. I keep my log4j.properties file in the same directory as my
hadoop configuration XML files. One of the ways log4j finds its
log4j.properties file is by CLASSPATH, and the configuration directory
is always in the CLAS
for hadoop 2.x, the log4j. properties file for each project should be in
src/test/resources
but there's a risk that tests in sub projects that include
hadoop-commons-test.jar (or other -test JARs, like hadoop-hdfs) may pick up
the version in the test jar ahead of any one that they have locally -so
