code: public void setZeroDigit(char zeroDigit) {
          this.zeroDigit = zeroDigit;
  
          // digitStrings or digits might be referencing a cached copy for
          // optimization purpose, so creating a copy before making a modification
          digitStrings = digitStrings.clone();
          digits = digits.clone();
  
          // Make digitStrings field and digits field in sync
          digitStrings[0] = String.valueOf(zeroDigit);
          digits[0] = zeroDigit;
  
          // Android patch (ticket #11903) begin.
              for (int i = 1; i < 10; i++) {
                  char d = (char)(zeroDigit + i);
                  digitStrings[i] = String.valueOf(d);
                  digits[i] = d;
              }
          // Android patch (ticket #11903) end.
      }
docs: Sets the character used for zero.
  <p>
  <b>Note:</b> When the specified zeroDigit is a Unicode decimal digit character
  (category:Nd) and the number value is 0, then this method propagate digit 1 to
  digit 9 by incrementing code point one by one.
  
  @param zeroDigit the zero character.
  @apiNote <strong>Discouraged:</strong> ICU 58 use