Get Bluetooth local mac address in Marshmallow

zmarties is right but you can still get the mac address via reflection or Settings.Secure:

  String macAddress = android.provider.Settings.Secure.getString(context.getContentResolver(), "bluetooth_address");

Access to the mac address has been deliberately removed:

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.

(from Android 6.0 Changes)

You can access Mac address from the file "/sys/class/net/" + networkInterfaceName+ "/address" ,where networkInterfaceName can be wlan0 or eth1.But Its permission may be read-protected,so it may not work in some devices.I am also attaching the code part which i got from SO.

public static String getWifiMacAddress() {        try {            String interfaceName = "wlan0";            List<NetworkInterface> interfaces = Collections                    .list(NetworkInterface.getNetworkInterfaces());            for (NetworkInterface intf : interfaces) {                if (!intf.getName().equalsIgnoreCase(interfaceName)) {                    continue;                }                byte[] mac = intf.getHardwareAddress();                if (mac == null) {                    return "";                }                StringBuilder buf = new StringBuilder();                for (byte aMac : mac) {                    buf.append(String.format("%02X:", aMac));                }                if (buf.length() > 0) {                    buf.deleteCharAt(buf.length() - 1);                }                return buf.toString();            }        } catch (Exception exp) {            exp.printStackTrace();        }         return "";    }