Java tutorial
//package com.java2s; import android.content.Context; import android.telephony.TelephonyManager; public class Main { private static Context matoContext; public static String getIMEI() { checkNull(); TelephonyManager telephonyManager = (TelephonyManager) matoContext .getSystemService(Context.TELEPHONY_SERVICE); String imei = telephonyManager.getDeviceId(); return imei == null ? "null" : imei; } public static void checkNull() { if (matoContext == null) { throw new NullPointerException("context is null"); } } }