mime4j provides a parser, MimeStreamParser, for e-mail message streams
in plain rfc822 and MIME format. The parser uses a callback mechanism to
report parsing events such as the start of an entity header, the start
of a body, etc. If you are familiar with the SAX XML parser interface
you should have no problem getting started with mime4j.

The parser only deals with the structure of the message stream. It won't
do any decoding of base64 or quoted-printable encoded header fields and
bodies.

The parser has been designed to be extremely tolerant against messages
violating the standards.

mime4j can also be used to build a tree representation of an e-mail
message using the Message class. Using this facility mime4j
automatically handles the decoding of fields and bodies and uses
temporary files for large attachments.