I need to obtain the MAC address of my android device using Java. I've searched online, but I haven't found anything useful.
As was already pointed out in the comment, the MAC address can be received via the WifiManager.
WifiManager manager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo info = manager.getConnectionInfo();
String address = info.getMacAddress();
Also do not forget to add the appropriate permissions into your AndroidManifest.xml
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
Please refer to Android 6.0 Changes.
To provide users with greater data protection, starting in this release, Android removes programmatic access to the device’s local hardware identifier for apps using the Wi-Fi and Bluetooth APIs. The WifiInfo.getMacAddress() and the BluetoothAdapter.getAddress() methods now return a constant value of 02:00:00:00:00:00.
To access the hardware identifiers of nearby external devices via Bluetooth and Wi-Fi scans, your app must now have the ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION permissions.