ApexBeginnernull-safetydefensive
Apply defensive null and empty collection handling in Apex
Real World Scenario
NullPointerException in production when optional lookup field blank on subset of records in batch.
Expected Answer
• Null-check relationship fields before dereferencing
• Empty list iteration safe but query empty IN () throws
• Optional chaining pattern with ternary or early continue
• Validate API inputs at controller entry
• Use String.isBlank for text fields not only null check
• Unit tests include null field edge case records
• Static analysis PMD null pointer rules in CI
Follow-Up Questions & Answers
Click to expand — each follow-up includes a direct, interview-ready answer
Direct answer: Null-check relationship fields before dereferencing Also consider: Empty list iteration safe but query empty IN () throws In practice: Optional chaining pattern with ternary or early continue Keep the solution simple and well-documented for the team.
Architect Perspective
Bulk data always includes incomplete records—null safety is not optional.