code: @Deprecated
      public static DateTimePatternGenerator getFrozenInstance(ULocale uLocale) {
          String localeKey = uLocale.toString();
          DateTimePatternGenerator result = DTPNG_CACHE.get(localeKey);
          if (result != null) {
              return result;
          }
  
          result = new DateTimePatternGenerator();
          result.initData(uLocale);
  
          // freeze and cache
          result.freeze();
          DTPNG_CACHE.put(localeKey, result);
          return result;
      }
docs: Construct a frozen instance of DateTimePatternGenerator for a
  given locale.  This method returns a cached frozen instance of
  DateTimePatternGenerator, so less expensive than the regular
  factory method.
  @param uLocale The locale to pass.
  @return A frozen DateTimePatternGenerator.
  @deprecated This API is ICU internal only.
  @hide original deprecated declaration
  @hide draft / provisional / internal are hidden on Android