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1Z0-811 Primitives, Strings and Operators Practice Question

A developer needs to build a SQL query string by concatenating many parts. Which approach is most efficient for repeated concatenation?

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

✓

Using StringBuilder.append()

StringBuilder.append() is efficient for many concatenations as it uses a mutable buffer. StringBuffer is synchronized and slower. String concatenation with '+' creates many intermediate objects. String.concat() also creates new objects.

Answer analysis

Option-by-option breakdown

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

✗
Using StringBuffer.append()
Why it's wrong here
StringBuffer.append() is synchronized, making it slower than StringBuilder.
✓
Using StringBuilder.append()
Why this is correct
StringBuilder.append() uses a mutable buffer without synchronization, making it the most efficient for repeated concatenation.
✗
Using String concatenation with +=
Why it's wrong here
String concatenation with '+' creates many intermediate String objects, which is inefficient.
✗
Using String.concat()
Why it's wrong here
Although the text is identical to option B, this option is considered incorrect because the question expects a single correct answer. StringBuilder.append() is correctly assigned to option B.

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1Z0-811 Primitives, Strings and Operators Practice Question

Why each option matters

Option-by-option breakdown

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