title: java -Dlog4j.configuration command not working
body: <p>i have a problem with Hadoop mapreduce in R, and in the logs i did find this :</p>
  
  <pre><code>log4j:WARN No appenders could be found for logger (org.apache.hadoop.ipc.Server).
  log4j:WARN Please initialize the log4j system properly.
  log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info
  </code></pre>
  
  <p>my problem is presented <a href="https://stackoverflow.com/questions/31052643/hadoop-job-log4jwarn-please-initialize-the-log4j-system-properly">here</a> with no reaction unfortunately , so after a lot of research i found that i need to tell where to find the log4j with this command :</p>
  
  <pre><code>-Dlog4j.configuration=file:path/log4j.properties
  </code></pre>
  
  <p>my question is WHERE , because i did this :
  java -Dlog4j.configuration=file:log4j.properties
  but in my terminal in ubuntu it shows me that i didn"t use java command correctly , nothing shows that the command workd or not , the output is like this :</p>
  
  <pre><code>usage: java [-option]class [args ...]
  ....
  </code></pre>
  
  <p>so i don't know where to type this command , any help will be apreciated .
   thank you</p>