android - error after updating entity with deleted properties -

I am trying to update my unit to remove one of the properties. I am using Google App Engine Datastore for my Android project. After making changes in my unit, I have also prepared end point classes and my code has been well prepared. I get an error even when I run my code, where I am putting records in my datastore against that update unit. Somehow it is still expecting the old (deleted) property values. Below is an error message

  java.io.IOException: com.google.appengine.repackaged.org.codehaus .jackson.map.JsonMappingException: (java.lang.NullPointerException) (  
 Any help is appreciated   
 
 
 Okay, I realized that after applying the unit, I was not re-applying my app on the app engine and so this was the issue. Or I realized that data (not real entity data) that are shown on the app engine datastore admin does not always exist. I believed that the Detection Operation (from Datastore Admin) was not successful.