Process Automation and Logic28% of the exam
Apex control flow, loops and collections
How if-else, switch and the five Apex loops execute, what break and continue do, how SOQL for loops chunk records, how lists, sets and maps behave while you iterate them, and how the safe navigation and null coalescing operators handle nulls.
Given a scenario, assess how Apex control flow statements will execute and when to apply different control flow statements.
~7 min read · 8 practice questions ·
What the exam expects
- Predict which branch of an if-else chain or
switch onruns, includingwhen elseand null. - Choose among do-while, while, traditional for, list or set iteration and SOQL for loops, and predict how many times each body runs.
- Tell
breakfromcontinueandreturnin a loop. - Iterate lists, sets and maps safely, and pick the collection whose rules (order, duplicates, keys) fit the job.
- Use the safe navigation (
?.) and null coalescing (??) operators to avoid a NullPointerException.
Key terms: when else (the switch default block); do-while (tests its condition after the body); SOQL for loop (iterates query results in chunks); safe navigation (?. returns null instead of throwing); null coalescing (?? supplies a fallback for null).
Key facts
switch expression types
- Detail
- Integer, Long, sObject, String, Enum
switch fall-through
- Detail
- None;
when elseis optional and must be last
do-while
- Detail
- Body always runs at least once
while
- Detail
- Condition tested first; body may never run
Loop types
- Detail
- Five: do-while, while, for, list or set iteration, SOQL for
break / continue
- Detail
- Exits the entire loop / skips to the next iteration
SOQL for loop, list format
- Detail
- Body runs once per 200 records
Modifying a collection mid-iteration
- Detail
- Not supported; causes an error
Map String keys
- Detail
- Case-sensitive; an existing key is overwritten by put
?. on null- Detail
- Returns null; right side not evaluated
Sources for this section (8)
- Switch Statementsdeveloper.salesforce.com (opens in a new tab)
- Do-While Loopsdeveloper.salesforce.com (opens in a new tab)
- While Loopsdeveloper.salesforce.com (opens in a new tab)
- Loopsdeveloper.salesforce.com (opens in a new tab)
- SOQL For Loopsdeveloper.salesforce.com (opens in a new tab)
- Iterating Collectionsdeveloper.salesforce.com (opens in a new tab)
- Mapsdeveloper.salesforce.com (opens in a new tab)
- Safe Navigation Operatordeveloper.salesforce.com (opens in a new tab)
- When does a do-while body run even though its condition is false?
- Why use the list format of a SOQL for loop when the loop body performs DML?
- What happens when no `when` value matches and there is no `when else`?
- Why would you choose a set over a list for a group of Ids?
- What does `con.Account?.BillingCity` return when the contact has no account?
The questions are free to read. Answers with their sources and self-grading are included with the pack.
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