GMail API for Java
Now in its 0.3.12, I think g4j is evolving gradually. I have just downloaded the source codes and was playing around with its sample application. So I wouldn’t know how great the API really is, but I’m going to find out about that sooner or later. This is what the author describes about his/her API:
GMailer API for Java (g4j) is set of API that allows Java programmer to communicate to GMail. With G4J programmers can made Java based application that based on huge storage of GMail.
An Email application, GMailer for Java is also built to demonstrate the usage of the API. It is planned to include minimalist email capabilities such as browse, search, read, send mail and download attachment.
And the screenshot for the example provided.