I am trying to develop applet on Java Card that is going to be recognizable for Android. I know there is IsoDep class that allows to communicate with ADPU protocol. However I want it to be recognizable without installing any app on device and without flashing Android system.
With NFC tag using NDEF is quite easy to write into tag that is later automatically recognizable as contact, link etc, without installing any app on device. Is it possible to do the same using contactless Java Card with NDEF or in other way?
The only way to trigger specific actions through NFC on an Android system (e.g. open URL, transfer a contact, etc.) without the need for a custom app is to use NDEF formatted data.
You would therefore need to create an applet on the card that implements the NFC Forum Type 4 Tag Operation specification (you can get the specification from the NFC Forum website). You can then embed an NDEF message into that applet.
You can find an implementation of the NFC Forum Type 4 Tag application in Java Card here: https://github.com/slomo/ndef-javacard (I have not tested this implementation yet, so I cannot comment on how well this implementation works.)