What will be the output of this code?

medium📝 Predict Output Q5 of 15

Java - Wrapper Classes

Double d = 4.5;
double result = d * 2;
System.out.println(result);

ACompilation error

B4.5 2

C9.0

D8.5

Step-by-Step Solution

Solution:

Step 1: Recognize unboxing in multiplication
Double d is unboxed to double primitive for multiplication.
Step 2: Calculate the multiplication
4.5 * 2 = 9.0, so result is 9.0 printed.
Final Answer:
9.0 -> Option C
Quick Check:
Unboxing allows Double in arithmetic operations [OK]

Quick Trick: Wrapper objects unbox automatically in math expressions [OK]

Common Mistakes:

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