code: public static RuntimeDatabase getRuntimeDatabase() {
          final String runtimeDatabase = getLocalProperty("runtimeDatabase");
          if (null == runtimeDatabase) {
              throw new RuntimeException("Please configures runtime database in local.properties!");
          }
  
          final RuntimeDatabase ret = RuntimeDatabase.valueOf(runtimeDatabase);
          if (null == ret) {
              throw new RuntimeException("Please configures a valid runtime database in local.properties!");
          }
  
          return ret;
      }
docs: Gets the runtime database.
  
  @return runtime database