Fair enough, there is a "Java Card". I'm not convinved that Java is running on any of my or your credit cards in your wallet today, though I'm not willing to bet on it.
https://www.cardlogix.com/product/cardlogix-credentsys-lite-...
And on another source:
Visa became the first large payment company to license JavaCard. Visa mandated JavaCard for all of Visa’s smartcard payment cards. Later, MasterCard acquired Mondex, and Peter Hill joined as their CTO, licensed JavaCard, and ported the Mondex payment platform to JavaCard.
Source: https://javacardforum.com/2022/07/28/the-birth-of-javacard/
(fwiw I have a bit of prior experience here)
Even fully passive NFC tags contain logic that needs power to talk NFC back to the reader, there’s no such thing as just reading data via NFC.
You know those 4 lights on a contactless card reader? They indicate different transaction stages between the card and the terminal. I don’t find them that useful because it’s so fast they all appear to light at the same time, but that’s what they are!
If they were just passive tags, they wouldn’t be very secure, they have cryptographic processors onboard with private keys that can sign stuff for the terminal and your bank. The specs for the interaction are all public if you’re interested (I wouldn’t be!) and lookup contactless EMV.
Though mind you, it is a very limited subset of Java, not the standard one.
It's almost bizarre what that thing does.