public abstract char charAt (int index)

Returns the char value at the specified index. An index ranges from zero to length() - 1. The first char value of the sequence is at index zero, the next at index one, and so on, as for array indexing.

If the char value specified by the index is a surrogate, the surrogate value is returned.

index    the index of the char value to be returned

Returns:  the specified char value

IndexOutOfBoundsException     if the index argument is negative or not less than length()