Kotlin - Null Safety
You want to safely convert a Java platform type String to uppercase in Kotlin, but the Java method may return null. Which Kotlin code is best?
You want to safely convert a Java platform type String to uppercase in Kotlin, but the Java method may return null. Which Kotlin code is best?
hard📝 Application Q8 of 15
Step-by-Step Solution
Solution:
Step 1: Handle possible null from Java method
Using safe call ?. avoids NullPointerException if getName() returns null.Step 2: Provide default value with Elvis operator
?: "UNKNOWN" ensures upper has a valid string even if getName() is null.Final Answer:
val upper = javaApi.getName()?.uppercase() ?: "UNKNOWN" -> Option AQuick Check:
Safe call + default value handles platform nulls well [OK]
Quick Trick: Use ?. and ?: to safely handle nullable Java returns [OK]
Common Mistakes:
MISTAKES- Using !! which throws exceptions
- Ignoring null possibility
- Using deprecated toUpperCase()
Master "Null Safety" in Kotlin
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