James Gosling has written that development of JavaCard 3.0 is almost complete, building on the popular JavaCard 2 API. The API comes in two flavours - Classic which is based around the previous version with some enhancements, and Connected Edition, which is where the real excitement is.
As the name suggests, Connected Edition brings about more communication possibilities and support for web applications. It also takes advantage of more memory being available. The VM is Java6 compatible and has full Java language support so you can use all the features you're comfortable with in Java such as generics and annotations. The only thing you'll find missing is support for floats. It also has a interfaces for HTTP and HTTPS. As you can see from the image below, the new APIs give you a lot more.
James notes that JavaCard 3.0 goes beyond the standard card use cases:
It is not just "Card" any more: With the newly added USB interface this technology can go beyond Smart Cards into devices like secure USB tokens, Secure Personal Databases, Embedded Servers, WebDAV compliant thumb drives and more.There's also a really useful NetBeans plugin to help you get started with JavaCard development.
You can go along to the Kenai page to find out more.