Using Google Drive APis with a scala play project

I Have been trying to adapt the java quick start guide for interacting with the google drive API's for a Scala Play project however I am having trouble with reading a the credential file in, it says it is not there however I have tried:

• Absolute path
• Path from content root
• Path from source root

But none of these have worked.

here is my project structure: Proj Structure

Here is the Error: Error

And Here is the Code I am using to try and read the file:

import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver
import com.google.api.client.googleapis.auth.oauth2.{GoogleAuthorizationCodeFlow, GoogleClientSecrets}
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport
import com.google.api.client.http.javanet.NetHttpTransport
import com.google.api.client.json.JsonFactory
import com.google.api.client.json.jackson2.JacksonFactory
import com.google.api.client.util.store.FileDataStoreFactory
import com.google.api.services.sheets.v4.SheetsScopes

import java.io.{File, FileNotFoundException, IOException, InputStreamReader}
import java.security.GeneralSecurityException
import java.util
import java.util.Collections

class GoogleService {
 private val applicationName: String = "Google Sheets API Java Quickstart"
 private val jsonFactory: JsonFactory = JacksonFactory.getDefaultInstance()
 private val tokenDirectoryPath: String = "tokens"

 private val scopes: util.List[String] = Collections.singletonList(SheetsScopes.SPREADSHEETS_READONLY)
 private val credentialsFilePath: String = "app/assets/credentials.json"

 @throws[IOException]
 private def getCredentials(HTTP_TRANSPORT: NetHttpTransport) = { // Load client secrets.
   val in = classOf[GoogleService].getResourceAsStream(credentialsFilePath)
   if (in == null) {
     System.out.printf(credentialsFilePath)
     throw new FileNotFoundException(s"Resource not found: $credentialsFilePath")
   }
   val clientSecrets = GoogleClientSecrets.load(jsonFactory, new InputStreamReader(in))
   // Build flow and trigger user authorization request.
   val flow = new GoogleAuthorizationCodeFlow.Builder(HTTP_TRANSPORT, jsonFactory, clientSecrets, scopes).setDataStoreFactory(new FileDataStoreFactory(new File(tokenDirectoryPath))).setAccessType("offline").build
   val receiver = new LocalServerReceiver.Builder().setPort(8888).build
   new AuthorizationCodeInstalledApp(flow, receiver).authorize("user")
 }

 @throws[IOException]
 @throws[GeneralSecurityException]
 def main(args: String*
         ) {
   val httpTransport = GoogleNetHttpTransport.newTrustedTransport
   getCredentials(httpTransport)
 }
}