There are ten versions of the listResourceObject method. Some versions require that you supply a single resource ID, or a list of resources, or a Boolean to clear the cache or other caching details. Other versions provide the ability to specify that the method to run as a different user.
When implementing this method within a form or rule, clarify in comments which version of this method you are using. For example,
Lists the Groups on the AD-Austin resource starting at the OurGroups OU. It will leverage the server cache should this list be found there. Additional details in the Identity Manager formUtil javadocs under: public static java.util.List listResourceObjects(java.lang.String subjectString, java.lang.String objectType, java.lang.String resourceId, java.util.Map options, java.lang.String cacheList)