code: protected void saveBroker (File mapfile, HashMapIDBroker broker)
          throws RuntimeException
      {
          // bail if the broker wasn't modified
          if (!broker.isModified()) {
              return;
          }
  
          try {
              BufferedWriter bout = new BufferedWriter(new FileWriter(mapfile));
              broker.writeTo(bout);
              bout.close();
          } catch (IOException ioe) {
              throw new RuntimeException(
                  "Unable to store component ID map [mapfile=" + mapfile + "]", ioe);
          }
      }
docs: Stores a persistent representation of the supplied hashmap ID
  broker in the specified file.