Java: Multibyte string length

Question

I have a method which prints "header text" for command line programs, much like the syntax of Markdown:

1. =======================
2. This is a header string
3. =======================

This method takes a char c for lines 1 and 3 and repeats it n times based on the length of s.

String.length() works fine with the English alphabet, but how can I find the length (the visual length, that is) of a string containing foreign multibyte characters like "Å" and "Ç"?

Answer 1

String.length will be fine for those sorts of characters, as Java strings work in UTF-16, which is sufficient to represent the vast majority of characters in common use (Latin, Greek, Arabic, Hebrew, Chinese, Thai, Devanagari, ...).

If you might need to deal with characters above U+FFFF then you need to use codePointCount instead of length to cope with surrogate pairs.

Answer 2

String.length() is fine for most Unicode characters including Å and Ç.

A Java string is utf-16 encoded where each Character takes up 2 or 4 bytes.

Supplementary characters denotes the characters taking 4 bytes and is implemented by pairing two characters, in which case the codePointCount operation must be used instead of length.

Characters though most certainly exist in the standard unicode specification.