code: public void replaceTrackers(List<AnnounceEntry> trackers) {
          announce_entry_vector v = new announce_entry_vector();
  
          for (AnnounceEntry t : trackers) {
              v.push_back(t.swig());
          }
  
          th.replace_trackers(v);
      }
docs: If you want libtorrent to use another list of trackers for this torrent,
  you can use {@link #replaceTrackers(List)} which takes a list of the same
  form as the one returned from {@link #trackers()} and will replace it.
  If you want an immediate effect, you have to call {@link #forceReannounce()}.
  <p>
  The updated set of trackers will be saved in the resume data, and when
  a torrent is started with resume data, the trackers from the resume
  data will replace the original ones.
  
  @param trackers the list of trackers
  @see AnnounceEntry