You have a Java method fun getUser(): User returning a platform type. You want to safely get the user's email or return "unknown" if null. Which Kotlin code correctly handles this?

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Kotlin - Null Safety

You have a Java method fun getUser(): User returning a platform type. You want to safely get the user's email or return "unknown" if null. Which Kotlin code correctly handles this?

Aval email = getUser().email ?: "unknown"

Bval email = getUser()?.email ?: "unknown"

Cval email = getUser().email!!

Dval email = getUser().email

Step-by-Step Solution

Solution:

Step 1: Recognize platform type and possible nulls
getUser() returns a platform type; email might be null.
Step 2: Use safe call and Elvis operator
Using ?. safely accesses email; ?: provides fallback "unknown" if null.
Final Answer:
val email = getUser()?.email ?: "unknown" -> Option B
Quick Check:
Safe call + fallback handles null platform types safely [OK]

Quick Trick: Use ?. with ?: to safely access nullable Java values [OK]

Common Mistakes:

MISTAKES

Using non-null assertion (!!) risking runtime crash
Ignoring possible null from platform type
Not providing fallback for null values

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More Kotlin Quizzes

You have a Java method fun getUser(): User returning a platform type. You want to safely get the user's email or return "unknown" if null. Which Kotlin code correctly handles this?

Step 1: Recognize platform type and possible nulls

Step 2: Use safe call and Elvis operator

Final Answer:

Quick Check:

Want More Practice?