NumberFormat format = NumberFormat.getInstance();
  format.setRoundingMode(RoundingMode.DOWN);
  format.setMaximumFractionDigits(2);
  System.out.println(format.format(4.7777));

String numberString = "137.99999999999";
int indexOfDecimal = numberString.indexOf('.');
Double truncatedNumber = new Double(numberString.subString(0,indexOfDecimal+2));