Is there a way to access a wireless phone's Electronic Serial Number (ESN) using J2ME?

Bill Day

The J2ME APIs do not specify any mechanism for accessing an ESN. (An ESN is a number built into a phone which may be used to uniquely identify that particular mobile handset.)

One of the reasons: Many devices do not contain ESNs for cost reasons.

It is possible that a manufacturer could provide an OEM- or device-specific Java API to access ESNs, in which case if you used the API, you would need to realize that your J2ME application was no longer portable to all devices.

Alternatively, you can track a user's access with a standard server-based mechanism such as username/password.