Java Checksum

Imported from previous forum

Can you help me out
with how to calculate
the checksum in Java.

This is what I’ve done
so far:

Ex: String fix_message = "8=FIX.4.2^A9=16^A35=A^A98=0^A108=1^A";

First of all, am I using the wrong delimiter?
Also would the checksum be 031?

Thanks,

Zeke