String[] types = new String[mime_types_.size()]; types = (String[]) mime_types_.toArray(types);
Set type_set = stores_by_mime_.keySet();  String[] types = new String[type_set.size()]; types = (String[]) type_set.toArray(types);
  public String[] getStoreMIMETypes()  {    String[] types = new String[mime_types_.size()];    types = (String[]) mime_types_.toArray(types);        return types;  }