JSP/Java Servlet owncloud alternative

Is there a good JSP/Java servlet alternative to owncloud? While I am aware it's possible to run apache or nginx to do php in front of tomcat I'd like to avoid deploying two servers if possible.

What functionality from ownCloud do you need?

The core technology of ownCloud is WebDAV, and Tomcat includes a WebDAV implementation, so there is at least a starting point.

Yea I'm aware tomcat includes web dav. What I'd really like is the ability to upload files from my browser without a dedicated WebDAV client. As well as the ability to create directories and have thumbnails on images. It would be really nice to have some form of document editor but I'm not worried if I can't do that.