title: Android duplicate class error when including Apache POI
body: <p>I've got a problem with the apache poi excel api (xlsx). I'm using android studio and I've added the poi libs to the "libs" folders. This error is popping up for some reason (see below). How would I solve it?, could you please explain how you identified the issue?</p>
  
  <p>xmlbeans-2.6.0, poi-ooxml-schemas-3.10.1-20140818, poi-ooxml-3.10.1-20140818, poi-3.10.1-20140818, log4j-1.2.13, junit-4.11, dom4j-1.6.1, commons-logging-1.1, commons-codec-1.5</p>
  
  <p>Thanks!</p>
  
  <p>My build.gradle looks like the following (excluding the generic other stuff)...</p>
  
  <blockquote>
    <p>dependencies {
        compile fileTree(include: ['*.jar'], dir: 'libs') }</p>
    
    <p>android {
        packagingOptions {
            exclude 'META-INF/LICENSE'
            exclude 'META-INF/NOTICE'
            exclude 'META-INF/LICENSE.txt'
            exclude 'META-INF/NOTICE.txt'
        } }</p>
  </blockquote>
  
  <p>My app.iml has no duplicate entries either...</p>
  
  <p>Error</p>
  
  <blockquote>
    <p>Error:Class org.apache.xmlbeans.xml.stream.Location has already been
    added to output. Please remove duplicate copies. compiler that did not
    target the modern .class file format. The recommended
    (org.apache.log4j.chainsaw.ControlPanel$1) that doesn't come with an
    associated EnclosingMethod attribute. This class was probably produced
    by a solution is to recompile the class from source, using an
    up-to-date compiler
        1 error; aborting</p>
  </blockquote>