Before updating a field ABC, I need to check whether the field is passed as null/blank, if yes, then dont update it.

Can someone advise if there is a difference between the two options below, and if yes, what I should be aware of? I am interested if wither there is a best practice, potential compile errors, or anything else.

Option 1:
if ( null != ABC && '' != ABC ) {
               abc.ABC__c = ABC;               
            }

Option 2:
if ( ABC != null && ABC != '' ) {
               abc.ABC__c = ABC;               
            }

Thank you!

Before updating a field ABC, I need to check whether the field is passed as null/blank, if yes, then dont update it.

Can someone advise if there is a difference between the two options below, and if yes, what I should be aware of? I am interested if wither there is a best practice, potential compile errors, or anything else.

Option 1:
if ( null != ABC && '' != ABC ) {
               abc.ABC__c = ABC;               
            }

Option 2:
if ( ABC != null && ABC != '' ) {
               abc.ABC__c = ABC;               
            }

Thank you!

I need to have lists refresh when a new record is added. I would think that the Choose How Lists Refresh option and Push Notifications handle this, but that does not seem to work. Please help!

I am thinking about using a Email Service to handle inbound e-mails on a case.

The reason is that I have to flip the status of case based upon some subject text in the e-mail.

I will assume that the inbound e-mail have the Thread Id of the case (e.g ref:00D7KKMD.50075Ertx:ref)

How does one match the Thread Id to a case using Apex code.

I can't find the Thread Id field in the case object.

Email Templates does have a field called Case.Thread_Id, but I can't find when I do [select id from case where Thread_Id = ...]