Java, like NT, was originally UCS-2 and moved to UTF-16 when it became clear that UCS-2 won't suffice. APIs that operate on units (anything involving "char"s [t

Java, like NT, was originally UCS-2 and moved to UTF-16 when it became clear that UCS-2 won't suffice. APIs that operate on units (anything involving "char"s [the type], CharSequences and so on) are legacy and, when used, are almost certainly used incorrectly. Note that newer APIs on String also use the word "char", but the type "int", these are actually operating on code points and not CUs, ie. these APIs are correct. (Note that java.lang.Character is a char, so wrong. I think there is no CodePoint type or similar that wraps int.)