title: GCP - GoogleCredential vs GoogleCredentials
body: <p>I'm creating GPC clients for BigQuery &amp; Transfer API, using GCP Java API.
  To each client I need to initiate different type of credentials - </p>
  
  <p><a href="https://developers.google.com/api-client-library/java/google-api-java-client/reference/1.20.0/com/google/api/client/googleapis/auth/oauth2/GoogleCredential" rel="noreferrer">GoogleCredential javadoc</a> - for Transfer API</p>
  
  <p><a href="http://google.github.io/google-auth-library-java/releases/0.6.0/apidocs/com/google/auth/oauth2/GoogleCredentials.html" rel="noreferrer">GoogleCredentials javadoc</a> - for BigQuery</p>
  
  <p>Is there a convenient way to convert between the two so I won't need to manage reading two types of credentials?</p>
  
  <p>Also - could anyone reason why there was a need for these two types?</p>