Android NetworkInterface. What are the meanings of names of NetworkInterface?

Since Android is based on Linux, Linux network interface naming patterns apply to Android devices.

Here's some resources on *nix network interface naming

• a tour of classic Linux network interface names
• new predictable interface names
• a good StackOverflow question

To summarize:

lo usually stands for the loopback interface (localhost)

wlan usually stands for a wireless networking interface

rmnet interfaces are usually associated with cellular connections and usb tethering

sit interfaces are associated with tunneling IPv6 over IPv4

p2p interfaces are usually associated with peer-to-peer connections (perhaps your Android device's WiFi Direct support?)

dummy interfaces provide special aliases for the loopback interface

ap or swlan interfaces (depending on the Android distribution) can be found when the Mobile Hotspot (Access Point) is activated on an Android device. It might also be associated with a regular wlan interface though (observed on devices where it is not possible to activate the WiFi connection and Mobile Hotspot at the same time, e.g. Android 9 on Galaxy Tab S2).