On this page:

http://www.mongodb.org/display/DOCS/Java+Language+Center

This link:

http://api.mongodb.org/java/index.html

Redirects to the 1.3 docs. The latest release is 1.4.

E.g.

http://api.mongodb.org/java/1.3/index.html

Doesn't look like the 1.4 docs are available.