Get Error when i compile project

[pishguy]

Hi i get this error:

Error:Error converting bytecode to dex:
Cause: com.android.dex.DexException: Multiple dex files define Lio/realm/BaseRealm$1;
Error:Execution failed for task ':app:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: java.lang.UnsupportedOperationException

how can i resolve this problem and test your project? could you upload apk?