code: public String replaceFieldTypes(String pattern, String skeleton) {
          return replaceFieldTypes(pattern, skeleton, MATCH_NO_OPTIONS);
      }
docs: Adjusts the field types (width and subtype) of a pattern to match what is
  in a skeleton. That is, if you supply a pattern like "d-M H:m", and a
  skeleton of "MMMMddhhmm", then the input pattern is adjusted to be
  "dd-MMMM hh:mm". This is used internally to get the best match for the
  input skeleton, but can also be used externally.
  <p>Example code:{@sample external/icu/android_icu4j/src/samples/java/android/icu/samples/text/datetimepatterngenerator/DateTimePatternGeneratorSample.java replaceFieldTypesExample}
  @param pattern input pattern
  @param skeleton For the pattern to match to.
  @return pattern adjusted to match the skeleton fields widths and subtypes.