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Salvatore ParacuolloSalvatore Paracuollo 

Help for few questions

Hello, I have a doubt on this question:

which code block returns the listview of an Account object using the following debug statement?
A. ApexPages.StandardSetController controller = new Apexpages.StandardSetController([SELECT id FROM Account LIMIT 1]);
B. ApexPages.StandardController controller = new ApexPages.StandardController(Database.getQueryLocator('select id from account limit 1')).
C. ApexPages.StandardController controller = new ApexPages.StandardController([SELECT id FROM Account LIMIT 1]);
D. ApexPages.StandardSetController controller = new ApexPages.StandardSetController(database.getQueryLocator('select id from Account Limit 1'))

The correct answer seems to be D, but I didn0t understand why D and not A (trying by dev console, both worked): can anyone help me, please?
Alain CabonAlain Cabon

 A and D should work as both constructors are correct.

[SELECT id FROM Account LIMIT 1] is ambiguous.

if ([SELECT Name FROM Account LIMIT 1] instanceof List<account>) {system.debug('test list ok');}  // OK

if ([SELECT Name FROM Account LIMIT 1] instanceof account) {system.debug('test account ok');}  // ERROR

List<account> accountList = [SELECT Name FROM Account LIMIT 1];
system.debug('accountList name : ' + accountList[0].name);

... but this also works (limit 1 is ambiguous): 

account acc = [SELECT Name FROM Account LIMIT 1];
system.debug('acc name : ' +;  // OK

Alain CabonAlain Cabon

List<account> accountList = [SELECT Name FROM Account LIMIT 20];
ApexPages.StandardSetController ssc = new ApexPages.StandardSetController(accountList);


List<account> accountList = [SELECT Name FROM Account LIMIT 1];
ApexPages.StandardSetController ssc = new ApexPages.StandardSetController(accountList);


ApexPages.StandardSetController ssc = new ApexPages.StandardSetController([SELECT Name FROM Account LIMIT 1]);

The all thing works as long as LIMIT 1 is an instance of List<Account> (check with instanceof)

Perhaps a very bad practice (ambiguous) but that works with LIMIT 1. 

Alain CabonAlain Cabon
When there is no account at all (zero account), perhaps D is still working but there is not this  basic assumption in the wording of the question.