code: public Map<Object, String> read(Reader reader) throws IOException {
          Map<Object, String> cvs = new HashMap<>();
          try (CSVReader r = new CSVReader(reader, '\t')) {
              String[] cols;
              int i = 1;
              while ((cols = r.readNext()) != null) {
                  switch (cols.length) {
                      case 0:
                          break;
                      case 1:
                          String col0 = cols[0];
                          if (col0.length() > 1) {
                              cvs.put(col0, "");
                          }
                          break;
                      case 2:
                          cvs.put(cols[1], cols[0]);
                          break;
                      default:
                          throw new IOException("Invalid mapping in line " + i + ": mapping has length " + cols.length);
                  }
                  i++;
              }
          }
          return cvs;
      }
docs: Closes the supplied reader.
  
  @param reader
  @return
  @throws IOException