code: private void dropAllEntities() {
  
          for (final MappedEntity mappedEntity : ImmutableList.copyOf(entities.values())) {
              try {
                  dropEntity(mappedEntity.getEntity());
              } catch (final DatabaseEngineException ex) {
                  logger.debug(String.format("Failed to drop entity '%s'", mappedEntity.getEntity().getName()), ex);
              }
          }
      }
docs: Drops all entities associated with this engine.
  
  @since 2.1.13