Working with Arrays and Collections →mediumMultiple ChoiceObjective-mapped

1Z0-829 Working with Arrays and Collections Practice Question

What does the Map.merge() method do if the specified key is absent?

⚠ Common exam trap

Oracle often tests the misconception that the remapping function is always called, leading candidates to incorrectly choose option A, when in fact the function is only invoked for existing keys.

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

✓

Associates the key with the given value

When the specified key is absent in the map, the `Map.merge()` method associates the key with the given value without invoking the remapping function. This is specified in the Java API documentation: if the key is not present (or maps to null), the key is associated with the given non-null value.

Answer analysis

Option-by-option breakdown

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

✗
Calls the remapping function with null and the value
Why it's wrong here
Remapping is called when key is present.
✓
Associates the key with the given value
Why this is correct
If absent, put value.
✗
Throws NullPointerException
Why it's wrong here
Only if value or remapping is null.
✗
Removes the key if present
Why it's wrong here
That's not merge.

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1Z0-829 Working with Arrays and Collections Practice Question

Why each option matters

Option-by-option breakdown

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