Primitives as Types - The Java Programming Language - page 291

public static int codePointCount(CharSequence seq, int start, int
end)
Returns the number of code points defined in
seq.charAt(start) to seq.charAt(end) , taking into account sur-
rogate pairs. Any unpaired surrogate values count as one
code point each.
public static int offsetByCodePoints(char[] seq, int start, int
count, int index, int numberOfCodePoints)
Returns the index into the array, that is numberOfCodePoints
away from index , considering only the subarray from
seq[start] to seq[start+length] , taking into account surrogate
pairs. This allows you to skip a given number of code points,
without having to manually loop through the array, keeping
track of surrogate pairs. If any unpaired surrogates are found,
they count as one code point.
public static int offsetByCodePoints(CharSequence seq, int index,
int numberOfCodePoints)
Returns the index into the CharSequence , that is number-
OfCodePoints away from index , taking into account surrogate
pairs.
public static char[] toChars(int codePoint)
Converts a code point to its UTF -16 representation as a one-
or two- char array. If codePoint is not valid, IllegalArgumentEx-
ception is thrown.
public static int toChars(int codePoint, char[] dst, int dstBegin)
Converts a code point to its UTF -16 representation, storing it
in dst starting at dst[dstBegin] and returning the number of