When using JavaMail to encode various header fields and the message body, what can you expect a client to handle on the other end? Which character sets can you expect all commonly used clients to recognize? Which fields will they decode? Do they adhere to the RFC822 and RFC2047 standards?

Jeff Gay

The MIME standards always default to the US English character set; ASCII. If you want to guarantee that the message is going to be readable then use the default; ASCII.

If the mail client is MIME compliant then all fields can be encoded, both delivery and character set.