title: spring data mongodb _id mapping preference
body: <p>I am using spring data mongodb framework in my java application to persist my application data in mongodb. In my java model class I have two fields. </p>
  
  <p>1) A field objId with @Id annotation on it.
  2) A field id</p>
  
  <p>with respect to mapping to _id key in the mongodb document saved, which one will get preference or will I get an error for multiple mapping. I am using spring data mongo 1.6.1. I know I could have tested this out but I do not have local environment setup.</p>