How to avoid duplicate IMEI NO of phone in Android Application?

I wanna avoid same request of multiple user from same device in my android application. For that case, I wanna avoid duplicate IMEI NO of phone that how one user can’t request an event from multiple user ID using same device.

How can i do this?

How can drop a pin on specific location?

If one user registered on my application, then drop a pin on google map that can I specify the user’s in future to search as another users nearby. How can I do this on android application development?

Reference –

import android.telephony.TelephonyManager;
import android.content.Context;

TelephonyManager telephonyManager;
telephonyManager = (TelephonyManager) getSystemService(Context.
 * getDeviceId() returns the unique device ID.
 * For example,the IMEI for GSM and the MEID or ESN for CDMA phones.
String deviceId = telephonyManager.getDeviceId();

You will need to request for permission – android.permission.READ_PHONE_STATE
Also, verify if this requires runtime permission on M and above!