What is the output of the following code?

medium📝 Predict Output Q4 of 15

Java - Wrapper Classes

Integer a = 10;
int b = a + 5;
System.out.println(b);

A10

B15

CCompilation error

DNullPointerException

Step-by-Step Solution

Solution:

Step 1: Analyze autoboxing and unboxing
Variable a is an Integer object holding 10. When used in arithmetic, it is unboxed to int.
Step 2: Calculate expression
Unboxed a (10) plus 5 equals 15, which is stored in b and printed.
Final Answer:
15 -> Option B
Quick Check:
Unboxing converts wrapper to primitive for arithmetic [OK]

Quick Trick: Wrapper unboxes automatically in arithmetic expressions [OK]

Common Mistakes:

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