android 环信SDK Error:Execution failed for task ':app:transformClassesWithDexForDebug'.

 
这是什么问题 求大神们回复下

Error:Execution failed for task ':MALL:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: Error while executing java process with main class com.android.dx.command.Main with arguments {--dex --num-threads=4 --multi-dex --main-dex-list C:\SVNApp\svnBookids\MALL\build\intermediates\multi-dex\debug\maindexlist.txt --output C:\SVNApp\svnBookids\MALL\build\intermediates\transforms\dex\debug\folders\1000\1f\main C:\SVNApp\svnBookids\MALL\build\intermediates\transforms\jarMerging\debug\jars\1\1f\combined.jar}