The answer is 1, not 2, because the `BinarySearch` method returns the index of the found element, and in Java, array indices are zero-based. When searching for the value 2 in the sorted array {1, 2, 3, 4, 5}, the method locates the element at position 1 (the second slot), so the return value is 1. On the Oracle Java Foundations 1Z0-811 exam, this question tests your understanding that `binarySearch` always returns the index, not the value itself, and that it requires a sorted array to function correctly. A common trap is confusing the element’s value with its position—students often mistakenly output the value 2 instead of the index 1. To avoid this, remember the memory tip: “Index starts at zero; binarySearch gives the slot, not the score.”
1Z0-811 Arrays and Methods Practice Question
This 1Z0-811 practice question tests your understanding of arrays and methods. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
public class Search {
public static int findIndex(int[] arr, int value) {
for (int i = 0; i < arr.length; i++) {
if (arr[i] == value) {
return i;
}
}
return -1;
}
public static void main(String[] args) {
int[] data = {5, 10, 15, 20};
int idx = findIndex(data, 15);
System.out.println(idx);
}
}
Refer to the exhibit.
public class Search {
public static int findIndex(int[] arr, int value) {
for (int i = 0; i < arr.length; i++) {
if (arr[i] == value) {
return i;
}
}
return -1;
}
public static void main(String[] args) {
int[] data = {5, 10, 15, 20};
int idx = findIndex(data, 15);
System.out.println(idx);
}
}
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
2
The code uses binarySearch on a sorted array. The array {1, 2, 3, 4, 5} is sorted, and the target value 2 is found at index 1 (0-based). The binarySearch method returns the index of the found element, so the output is 1. Option A is correct because the output is 1, not 2.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
2
Why this is correct
15 is at index 2.
Related concept
Read the scenario before looking for a memorised answer.
✗
-1
Why it's wrong here
Value is found.
✗
1
Why it's wrong here
Index of 15 is 2.
✗
3
Why it's wrong here
Index 3 is 20.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Oracle often tests the misconception that binarySearch returns the value itself rather than the index, or that the index is 1-based instead of 0-based.
Detailed technical explanation
How to think about this question
The binarySearch method in Java's Arrays class requires the array to be sorted; otherwise, results are undefined. It uses a binary search algorithm with O(log n) complexity. In real-world scenarios, this is efficient for large datasets, but developers must ensure the array is sorted before calling binarySearch to avoid incorrect results.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 1Z0-811 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Arrays and Methods — This question tests Arrays and Methods — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 2 — The code uses binarySearch on a sorted array. The array {1, 2, 3, 4, 5} is sorted, and the target value 2 is found at index 1 (0-based). The binarySearch method returns the index of the found element, so the output is 1. Option A is correct because the output is 1, not 2.
What should I do if I get this 1Z0-811 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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