SALESFORCE-PD1 Developer Fundamentals Practice Question
A developer is writing an Apex method and needs to store a collection of unique email addresses while maintaining fast lookup times. Which collection should the developer choose?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set<String>
Sets in Apex store unique elements and provide efficient membership testing methods like contains().
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
List<String>
Why it's wrong here
Lists allow duplicate elements and require linear scans to check for existence unless sorted.
- ✗
Queue<String>
Why it's wrong here
Apex does not have a native Queue collection type for general data storage.
- ✗
Map<String, Integer>
Why it's wrong here
Maps require both a key and a value, which is unnecessarily complex for simply storing unique strings.
- ✓
Set<String>
Why this is correct
Sets inherently prevent duplicate values and offer optimized lookup performance.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Salesforce exam blueprint
This SALESFORCE-PD1 practice question is part of Courseiva's free Salesforce certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SALESFORCE-PD1 exam.