hibernate - Grails createCriteria returning null criteria -

I am receiving a strange NullPointerException in grails 2.1.1.

  Hibernate CriteriaBuilder crit = FattoriIndicator.createCriteria () crit.createAlias ​​("Indicator", "Ind") ... // NPE here, because the underlying criteria is zero   
 
 The class is listed in hibernation  
 The other class is just right from the same working config file  
 The class has not been recently added, this is a For a long time   
 Certainly something is missing, but I can not see it.  
 EDIT: I'm sure that this code is configured correctly because this code works:  
  Hibernate Criteria builder aa = FattoriIndicatori .createcriteria () Number res = crit.get {estimates {count ()}}    
 
 
 The problem is That some methods work only on  HibernateCriteriaBuilder  when it gets  , close to  list ), etc.  
  Hibernate CriteriaBilder aa = FattoriIndicatori.createCriteria () Diff result = crit.list {createAlias ​​("Indicator", "Ind") eq ('ind.something', 'value') }   
 will work fine  list  method some initialization (underlying  criteria  example, which initially would be  null  ), Then closes the call to make the criteria, specification, then executes the resulting query and returns the result.