title: JHipster new version creates 500 server error "failed to map to source...to class" using Elasticsearch
body: <p>Generated a new JHipster application using v5.3.0 with Elasticsearch</p>
  
  <p>I'm using the same JDL that I used with the previous version of JHipster which worked successfully but could not deploy.</p>
  
  <p>I generate successful. No errors. No problems.</p>
  
  <p>When I open the application and try CRUD with my entities...works normally.</p>
  
  <p>For one of my entities, the Elasticsearch search returns a 500 server error.</p>
  
  <p>Again, this is just after generating the application. I haven't changed anything.</p>
  
  <p>This JDL worked in the last version. The failing entity works fine for all CRUD operations...just throws the error when doing a search. All the other entities work fine doing a search.</p>
  
  <p>The JSON response mentions "failed to map to source...to class".</p>
  
  <p>The generator created that mapping without errors. Why would it being failing during a search?</p>
  
  <p>Why do the other entities work OK?</p>
  
  <p>Any ideas? Anybody else have problems?</p>