code: public void removeMixin(final FedoraResource resource,
                              final Resource mixinResource,
                              final Map<String, String> nsPrefixMap) throws RepositoryException {
  
          final Node node = getJcrNode(resource);
          final String mixinName = getPropertyNameFromPredicate(node, mixinResource, nsPrefixMap);
          if (repositoryHasType(session, mixinName) && node.isNodeType(mixinName)) {
              node.removeMixin(mixinName);
          }
  
      }
docs: Remove a mixin from a node
  @param resource the resource
  @param mixinResource the mixin resource
  @param nsPrefixMap the prefix map
  @throws RepositoryException if repository exception occurred