Error: Error converting bytecode to dex

[Ndack]

Hi guys... I faced with this Problem.. For anyone having idea please help me

Information:Gradle tasks [:sample:assembleDebug] Error:Error converting bytecode to dex: Cause: com.android.dex.DexException: Multiple dex files define Lfr/ganfra/materialspinner/MaterialSpinner$1; Error:com.android.dex.DexException: Multiple dex files define Lfr/ganfra/materialspinner/MaterialSpinner$1; Error: at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:661) Error: at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:616) Error: at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:598) Error: at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171) Error: at com.android.dx.merge.DexMerger.merge(DexMerger.java:198) Error: at com.android.builder.dexing.DexArchiveMergerCallable.call(DexArchiveMergerCallable.java:61) Error: at com.android.builder.dexing.DexArchiveMergerCallable.call(DexArchiveMergerCallable.java:36) Error: at java.util.concurrent.ForkJoinTask$AdaptedCallable.exec(ForkJoinTask.java:1424) Error: at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) Error: at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) Error: at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) Error: at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157) Error:Execution failed for task ':sample:transformDexArchiveWithDexMergerForDebug'.

com.android.build.api.transform.TransformException: com.android.dex.DexException: Multiple dex files define Lfr/ganfra/materialspinner/MaterialSpinner$1; Information:BUILD FAILED in 2s Information:15 errors Information:0 warnings Information:See complete output in console