code: private List<TableInfo> getSchemaInfo(String persistenceUnit)
      {
          List<TableInfo> tableInfos = puToSchemaMetadata.get(persistenceUnit);
          // if no TableInfos for given persistence unit.
          if (tableInfos == null)
          {
              tableInfos = new ArrayList<TableInfo>();
          }
          return tableInfos;
      }
docs: Returns list of configured table/column families.
  
  @param persistenceUnit
  persistence unit, for which schema needs to be fetched.
  
  @return list of {@link TableInfo}