Method charAt

lib/java/lang/String.java:542–547

Returns the character at the specified offset in this string. @param index the zero-based index in this string. @return the character at the index. @throws IndexOutOfBoundsException if index < 0 or index >= length().

(int index)

     *             if {@code index < 0} or {@code index >= length()}.
     */
    public char charAt(int index) {
        if (0 <= index && index < count) {
            return value[offset + index];
        }
        throw new StringIndexOutOfBoundsException();
    }

    // Optimized for ASCII
    private char compareValue(char ch) {