code: public static String fieldName(Class<?> aClass,String regex){
  		
  		if(isNestedMapping(regex))
  		    return regex;
  				
  		String result = null;
  
  		for(Class<?> clazz: getAllsuperClasses(aClass))
  			if(!isNull(result = getFieldName(clazz, regex))) 
  				return result;
  		
  		return result;
  	}
docs: This method returns the name of the field whose name matches with regex.
  @param aClass a class to control
  @param regex field name
  @return true if exists a field with this name in aClass, false otherwise