title: Bulk API Error : InvalidBatch : Field name not found : Id
body: <p>I am trying to update contact records one field - Ext_Id__c via bulk api.  We have created the csv file with two columns and there no whitespaces in the header names. </p>
  
  <p>I am creating the job and pushing the batches to the job via a simple java client. the jab and batches are getting created successfully , however it's not updating the contact , instead it's gving below error:</p>
  
  <pre><code>BATCH STATUS:
  [BatchInfo  id='7512D000000XUV0QAO'
   jobId='7502D000000KWQuQAO'
   state='Failed'
   stateMessage='InvalidBatch : Field name not found : LastName'
   .......
  ..........
   numberRecordsProcessed='0'
   numberRecordsFailed='0'
   totalProcessingTime='0'
   apiActiveProcessingTime='0'
   apexProcessingTime='0'
  ]
  </code></pre>
  
  <p>I have all the neccesary access at field level for both fields. Can anyone please help?</p>