Hello!
The Java Card Specification define a way to load applets to your smart card, it is made thru a "external uploader" software. So, you need more than the JavaCard Development Kit tools to do it, a specific java card uploader (usually) from the same card's manufactor.
I know that it is possible to do via OpenPlatform (to card with this support) but it is a little bit hard to do.
Best Regards