Arrays and Methods →mediumMultiple ChoiceObjective-mapped

1Z0-811 Arrays and Methods Practice Question

Given the code:

int[] a = {1, 2, 3}; int[] b = {4, 5}; a = b; b[0] = 99; System.out.println(a[0]);

What is the output?

⚠ Common exam trap

The trap here is that candidates mistakenly think `a = b` copies the array values, leading them to believe `a[0]` retains its original value of 1 or that the arrays remain independent.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

After `a = b;`, both `a` and `b` reference the same array object. Modifying `b[0]` to 99 also changes `a[0]` because they share the same underlying array. Therefore, `a[0]` prints 99.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
3
Why it's wrong here
3 is from the original array a, but a no longer references that array.
✗
1
Why it's wrong here
1 was the value before reassignment, but a now references the array b.
✓
99
Why this is correct
After the assignment a = b, both references point to the same array; changing b[0] to 99 changes the shared array, so a[0] is 99.
✗
4
Why it's wrong here
4 was the original b[0] before it was changed to 99.

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1Z0-811 Arrays and Methods Practice Question

Why each option matters

Option-by-option breakdown

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