Importing a jar which includes an android service and trying to start it with NoClassDefFoundError

Question

Inside an Android Library project, I have a service which I need to use in other applications. That's why I have exported the library into a jar file and imported it successfully in new application, so that I can reuse my resources including the service. No compile time error is occurring, however when I call a method inside the library I get a runtime exception.

Library Code:

import com.example.user.exonelibrary.services.ScanningService;

public class ExoneManager {

    public SharedPreferences preferences;
    public SharedPreferences.Editor editor;
    private Context context;

    public ExoneManager(final Context context, final String token) {
        preferences = PreferenceManager.getDefaultSharedPreferences(context);
        this.context = context;
        editor = preferences.edit();
        editor.putString("TOKEN", token).commit();
    }

    public void start() {
        Intent intent = new Intent(context, ScanningService.class);
        context.startService(intent);
    }
}

The exception occurs after I take instance of class ExoneManager inside the activity of the application using the jar, when I call the start method which starts the service. This is the exception:

java.lang.NoClassDefFoundError: com.example.user.exonelibrary.services.ScanningService at com.example.user.exonelibrary.exone.ExoneManager.start(ExoneManager.java:32)

This is the manifest of the Library:

<?xml version="1.0" encoding="utf-8"?>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <service
        android:name=".services.ScanningService"
        android:enabled="true"
        android:exported="true"></service>
</application>