title: toDerInputStream rejects tag type 123
body: <p>I am trying to run the Get started with Datastore example at <a href="https://developers.google.com/datastore/docs/getstarted/start_java/" rel="nofollow noreferrer">https://developers.google.com/datastore/docs/getstarted/start_java/</a> trying it both from the command line and from Eclipse.</p>
  
  <p>In both environments, it is not able to connect to datastore and gives an I/O error message 'toDerInputStream rejects tag type 123'.</p>
  
  <p>Looking around, this may be because the private key file is in json format and perhaps it should the p12 - other than that the error message draws a blank.</p>
  
  <p>Could anyone point to something that would help me past this?</p>