Get unique identifier for an Android device

DeviceInfo.java

public class DeviceInfo {

    private static final String PREFERENCES = "DeviceInfo.PREFERENCES";
    private static final String KEY_DEVICEID = "DeviceId";

    /**
     * @return unique identifier string for the device
     */
    public static synchronized String getDeviceId(Context context) {
        SharedPreferences prefs = context.getSharedPreferences(PREFERENCES, 0);
        String value = prefs.getString(KEY_DEVICEID, null);
        if (value == null) {
            value = UUID.randomUUID().toString();
            prefs.edit().putString(KEY_DEVICEID, value).commit();
        }
        return value;
    }
}