Java - Wrapper Classes
Which of the following code snippets correctly uses autoboxing to assign a primitive int to an Integer object?
Which of the following code snippets correctly uses autoboxing to assign a primitive int to an Integer object?
easy📝 Syntax Q3 of 15
Step-by-Step Solution
Solution:
Step 1: Recognize autoboxing syntax
Autoboxing allows direct assignment of a primitive to its wrapper class without explicit constructor or casting.Step 2: Evaluate options
Integer num = 25; uses direct assignment which triggers autoboxing. Integer num = new Integer(25); uses explicit constructor (not autoboxing). Integer num = (Integer) 25; is invalid casting. Integer num = Integer.parseInt(25); is invalid usage of parseInt.Final Answer:
Integer num = 25; -> Option CQuick Check:
Direct assignment of int to Integer triggers autoboxing [OK]
Quick Trick: Assign primitive directly to wrapper for autoboxing [OK]
Common Mistakes:
- Using explicit constructor instead of autoboxing
- Trying to cast primitive to wrapper
- Misusing parseInt which returns int, not Integer
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