Попробуйте это (проверено на Android 10)
try {
const collection = java.util.Collections.list(java.net.NetworkInterface.getNetworkInterfaces());
const iterator = collection.iterator();
while (iterator.hasNext()) {
const nif = iterator.next(),
name = nif.getName();
if (name !== "wlan0") {
continue;
}
const macBytes = nif.getHardwareAddress();
if (macBytes !== null) {
const res = new java.lang.StringBuilder();
for (let i = 0; i < macBytes.length; i++) {
const b = macBytes[i];
const hex = java.lang.Integer.toHexString(b & 0xFF);
if (hex.length == 1) { hex = "0" + hex; }
res.append(hex + ":");
}
if (res.length > 0) {
res.deleteCharAt(res.length - 1);
}
console.log("Mac address: " + res);
}
}
} catch (err) {
console.log(err)
}