code: public boolean isCollection(Object obj, Field field) {
          try {
              Object val = field.get(obj);
              boolean isCollResource = false;
              if (val != null) {
                  isCollResource = CollectionResource.class.equals(val.getClass());
              }
              return (!isCollResource && !field.getType().equals(CollectionResource.class))
                      && (Collection.class.equals(field.getType()) || ArrayUtils.contains(field.getType().getInterfaces(),
                      Collection.class));
          } catch (Exception e) {
              throw new Siren4JRuntimeException(e);
          }
      }
docs: Determine if the field is a Collection class and not a CollectionResource class which needs special treatment.
  
  @param field
  @return