How to translate characters?

[Eric Douglas]

I pass a character into my XML/FO as □ and it shows on the PDF as
a square.
I'm trying to figure out what Java has for interpreting such code, and
it appears FOP just string searches and pulls out the number, in the
class org.apache.xmlgraphics.fonts.Glyphs.
Is this all it is, to search text for "&#" and ";" and find the
character value between, or is there an actual Java class/method for
translating such values?