IntStream to String

Java does not have a Char Stream, so when working with Strings and constructing a Stream of Characters, an option is to get a IntStream of code points using String.codePoints() method. So IntStream can be obtained as below:

public IntStream stringToIntStream(String in) {
  return in.codePoints();
}

It is a bit more involved to do the conversion other way around i.e. IntStreamToString. That can be done as follows:

public String intStreamToString(IntStream intStream) {
  return intStream.collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append).toString();
}