How can I get the Ril serial number for Motorola MOTO X?

Question

I made an application for a ril serial number. Samsung works great !! but, tested in Motorola MOTO X, it shows nothing!

The code I use is as follows:

String serial = null; try { Class<?> c = Class.forName("android.os.SystemProperties"); Method get = c.getMethod("get", String.class); serial = (String) get.invoke(c, "ril.serialnumber"); } catch (Exception ignored) { }