The Unity-ACRA plugin easily lets you keep track of crashes that have been caused by your native Java code by using ACRA.
The following steps illustrate how to integrate the Unity-ACRA plugin:
Change the value for fromeurl inside the ExtendedApplication.java to the your crash report url.
Copy the UnityARCA\bin\unityarca.jar folder into the Assets\Plusgings directory of your Unity project Unity
add the value for application\android:name for the AndroidManifest.xml (Assets/Plugins/Android) to "com.example.unityarca.ExtendedApplication".