code: public String[] readTarget(Reader reader) throws IOException {
          Collection<String> targetColl = read(reader).values();
          Set<String> targets = new HashSet<>();
          for (String target : targetColl) {
              targets.add(target);
          }
          return targets.toArray(new String[targets.size()]);
      }
docs: Closes the supplied reader.
  
  @param reader
  @param colNum
  @return
  @throws IOException