Online PDI Questions Video

The Boolean isOK variable is declared but not initialized, meaning its value is null by default in Apex.

The code evaluates the if-else conditions in sequence:

Condition 1: isOK == false && theString == 'Hello'

isOK is null, so this evaluates to false.

Condition 2: isOK == true && theString == 'Hello'

Again, isOK is null, so this evaluates to false.

Condition 3: isOK != null && theString == 'Hello'

isOK is null, so isOK != null evaluates to false.

Else block: None of the above conditions are true, so the code enters the else block and sets x = 4.

References:

Apex Boolean Data Type

A master-detail relationship from Engineering_Support__c to Opportunity allows multiple child Engineering_Support__c records to be associated with a single parent Opportunity. It also enables roll-up summary fields to aggregate data from the child records onto the parent Opportunity.

The recordSetVar attribute of the tag allows a Visualforce page to handle multiple records, which is ideal for list buttons that display a page for bulk editing.

Why not other options?

A: Standard controllers can be extended, but using recordSetVar is the direct and best-supported method for this scenario.

B: There is no such concept as a "Custom List Controller" in Visualforce.

C: is not a valid Visualforce tag.

References:

Visualforce Standard Controller with RecordSetVar

The Lightning Out library allows a Lightning Web Component to be embedded in a Visualforce page. This approach is the most suitable to make the LWC accessible in Salesforce Classic.