title: Multiple dex files define Landroid/support/v13/app/FragmentCompatICS
body: <p>I ported an Eclipse project to Android Studio IDE, the project was using <strong>android-support-v4</strong>, <strong>android-support-v13</strong> and <strong>appcompat_v7</strong> libraries, everything was fine but when I used Android Studio I got the following error each time I tried to run the project:</p>
  
  <pre><code>UNEXPECTED TOP-LEVEL EXCEPTION:
  com.android.dex.DexException: Multiple dex files define Landroid/support/v13/app/FragmentCompatICS;
      at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
      at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
      at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
      at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
      at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
      at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:454)
      at com.android.dx.command.dexer.Main.runMonoDex(Main.java:302)
      at com.android.dx.command.dexer.Main.run(Main.java:245)
      at com.android.dx.command.dexer.Main.main(Main.java:214)
      at com.android.dx.command.Main.main(Main.java:106)
  Error:Execution failed for task ':app:dexDebug'.
  &gt; com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/usr/lib/jvm/java-8-oracle/bin/java'' finished with non-zero exit value 2
  Information:BUILD FAILED
  </code></pre>
  
  <p>Note: it works once I cleaned the project, then the same error happened again next run, so I have to clean each time I run.</p>
  
  <p>Anyone have any idea why this keep happenning?</p>