code: private static String truncateOffsetPattern(String offsetHM) {
          int idx_mm = offsetHM.indexOf("mm");
          if (idx_mm < 0) {
              throw new RuntimeException("Bad time zone hour pattern data");
          }
          int idx_HH = offsetHM.substring(0, idx_mm).lastIndexOf("HH");
          if (idx_HH >= 0) {
              return offsetHM.substring(0, idx_HH + 2);
          }
          int idx_H = offsetHM.substring(0, idx_mm).lastIndexOf("H");
          if (idx_H >= 0) {
              return offsetHM.substring(0, idx_H + 1);
          }
          throw new RuntimeException("Bad time zone hour pattern data");
      }
docs: TODO This code will be obsoleted once we add hour pattern data in CLDR