Read the product offerings here to get acquainted with what's available. NOTE: All three options result in valid SSL certs accepted by Java and your browser without the "This Cert Is Invalid" message you get for self-signed certs.
Products: https://www.startssl.com/?app=39
I use StartSSL, class 2 ($60 for a full year of unlimited cert & wildcard cert generation where each generated cert is valid for up to 3 years.)
See the following page for CSR generation: CloudFront - SSL for Custom Domains