code: public static DataSourceBackendId getInstance(String id) {
          DataSourceBackendId result = cache.get(id);
          if (result == null) {
              id = id.intern();
              result = new DataSourceBackendId(id);
              cache.put(id, result);
          }
          return result;
      }
docs: Creates a data source backend id.
  
  @param id the id {@link String}. Cannot be <code>null</code>.
  @return a {@link DataSourceBackendId}.