code: private String getConcatenationPattern(ULocale locale) {
          ICUResourceBundle rb = (ICUResourceBundle) UResourceBundle.getBundleInstance(ICUData.ICU_BASE_NAME, locale);
          ICUResourceBundle dtPatternsRb = rb.getWithFallback("calendar/gregorian/DateTimePatterns");
          ICUResourceBundle concatenationPatternRb = (ICUResourceBundle) dtPatternsRb.get(8);
          if (concatenationPatternRb.getType() == UResourceBundle.STRING) {
              return concatenationPatternRb.getString();
          } else {
              return concatenationPatternRb.getString(0);
          }
      }
docs: Retrieves the concatenation DateTime pattern from the resource bundle.
  @param locale Locale to retrieve.
  @return Concatenation DateTime pattern.