Is there a character within the Math API that allows for representing the character π?
You don't even need to use the Math API. In Java source code, this:
\u03C0
is equivalent to this:
π
and you can even use it in an identifier; these two are equivalent:
final String \u03C0 = "\u03C0";
final String π = "π";
(As the spec puts it:
A Unicode escape of the form
\uxxxx, where xxxx is a hexadecimal value, represents the UTF-16 code unit whose encoding is xxxx. This translation step allows any program to be expressed using only ASCII characters.
See http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.2.)