code: protected void deleteCollection() throws PolicyIndexException {
  
          // get root collection management service
          Collection rootCol;
          try {
              rootCol = DatabaseManager.getCollection(m_databaseURI + ROOT_COLLECTION_PATH ,m_user, m_password);
              CollectionManagementService mgtService = (CollectionManagementService) rootCol.getService("CollectionManagementService", "1.0");
  
              // delete the collection
              mgtService.removeCollection(m_collectionName);
  
              log.debug("Policy collection deleted");
          } catch (XMLDBException e) {
              throw new PolicyIndexException("Error deleting collection " + e.getMessage(), e);
          }
      }
docs: delete the policy collection from the database
  @throws PolicyIndexException