Describe the Implications of Compound Data Types in Apex Programming. PLATFORM-DEVELOPER-II Practice Questions (Page 4)

Questions 16–20

1. 16expert · hard

   A developer has a List<Integer> numbers = new List<Integer>{1, 2, 3, 4, 5}; and needs to remove all even numbers from the list. Which code snippet correctly removes all even numbers?

   • Anumbers.removeIf(num -> Math.mod(num, 2) == 0);
   • Bfor (Integer i = 0; i < numbers.size(); i++) { if (Math.mod(numbers[i], 2) == 0) { numbers.remove(i); } }
   • Cfor (Integer i = numbers.size() - 1; i >= 0; i--) { if (Math.mod(numbers[i], 2) == 0) { numbers.remove(i); } }
   • Dfor (Integer num : numbers) { if (Math.mod(num, 2) == 0) { numbers.remove(num); } }
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2. 17expert · hard

   A developer has a list of Lead records and needs to remove duplicates based on the Email field. The list may contain leads with null emails. The developer wants to keep the first occurrence of each email and remove subsequent duplicates. Which approach correctly handles this?

   • AUse a List<String> to track seen emails, and check contains before adding.
   • BUse a Set<String> to track seen emails, and iterate through the list, adding non-duplicate leads to a new list.
   • CUse a Set<Lead> to store leads, relying on the default sObject equality.
   • DUse a Map<String, Lead> keyed by Email, and put each lead into the map, overwriting duplicates.
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4. 18foundation · easy

   Which method is used to retrieve a value from a Map using its key in Apex?

   • Aretrieve(key)
   • Bfind(key)
   • Cvalue(key)
   • Dget(key)
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5. 19foundation · easy

   What is the primary purpose of a Map in Apex?

   • ATo store unique elements without any particular order
   • BTo store elements in a specific order with duplicates allowed
   • CTo store key-value pairs for efficient lookup by key
   • DTo represent a database record with fields
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6. 20application · medium

   A developer has a Map<Id, Account> accountMap and needs to update the Name field of the Account with a specific Id. Which code snippet correctly updates the value?

   • AaccountMap.put(accId, new Account(Name='New Name'));
   • BaccountMap.set(accId, 'New Name');
   • CaccountMap.Name = 'New Name';
   • DaccountMap.get(accId).Name = 'New Name';
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