code: public static boolean h2DataFileExists(Settings configuration) throws IOException {
          final File file = getH2DataFile(configuration);
          return file.exists();
      }
docs: Determines if the H2 database file exists. If it does not exist then the
  data structure will need to be created.
  
  @param configuration the configured settings
  @return true if the H2 database file does not exist; otherwise false
  @throws IOException thrown if the data directory does not exist and
  cannot be created