ByteCream has released today the fastest(*) Base64 encoder.

If you're using email (file attachements are encoded with Base64), XML
(binary data are often encoded), Webservices, Configuration (binary
values are often encoded) or LDAP (same reason), you can boost your
application today!
Adapters are available so you don't ever need to recompile your
application.

Fast Base64 Encoder API provides support for byte arrays, streams
(java.io), byte buffers and channels (java.nio).

Visit the product page at:
http://www.bytecream.com/products/base64/

(*) according to our tests