I have written a web application in Java. As a part of this application, I need to retrieve mails from Gmail, Yahoo and Hotmail. I am looking for open source free mail clients having GPL license. I came across many open source free mail clients like SqMail, Claws mail and Thunderbird. I am not able to figure our how should I go about integrating this mail client with my application written in Java. Do this mail clients have some code which I should copy in my Java file to use this client or how to do it?
Thank you in advance.
Used JavaMail to integrate Gmail with Java application