The java.lang.Character.valueOf(char c) returns a Character instance
representing the specified char value. If a new Character instance is
not required, this method should generally be used in preference to the
constructor Character(char), as this method is likely to yield
significantly better space and time performance by caching frequently
requested values.
 
This method will always cache values in the range '\u0000' to '\u007F',
inclusive, and may cache other values outside of this range.