title: Cloud Endpoints Collection Parameter and "operating on too many entity groups in a single transaction"
body: <p>I need pass a collection of objects as Google Cloud endpoint api paramter. There is a way to do that: <a href="https://stackoverflow.com/questions/14763061/cloud-endpoints-collection-parameter">encapsulate the list into another object</a> .  Then there is cross group issue, so I <a href="https://developers.google.com/appengine/docs/java/datastore/transactions#Using_Transactions" rel="nofollow noreferrer">explicitly enable it in persistence.xml</a> . But then there is another problem: I need upload hundreds objects and there is only up to <a href="https://developers.google.com/appengine/docs/java/datastore/transactions" rel="nofollow noreferrer">5 items</a> if doing cross group transaction.</p>
  
  <p>So how I'm able to solve the original problem ( upload collection of hundreds objects as google cloud endpoint api parameter) under these restrictions? Thanks.</p>