The correct fix is to change the loop to for (int i = 0; i < numbers.length; i++), which resolves the ArrayIndexOutOfBoundsException by starting at index 0 and stopping before index 5. The original code’s off-by-one error stems from initializing i at 1 and using the condition i <= numbers.length, which causes the loop to attempt accessing numbers[5]—an invalid index since Java arrays are zero-indexed and valid indices for a five-element array are 0 through 4. On the Oracle Java Foundations 1Z0-811 exam, this classic java array for loop index out of bounds off by one fix tests your understanding of array indexing and loop boundary conditions, a frequent trap where candidates mistakenly start at 1 or use <= instead of <. Remember the memory tip: “Zero to length minus one” — always start at 0 and use strict less-than to stay within bounds.
1Z0-811 Java Basics and Syntax Practice Question
This 1Z0-811 practice question tests your understanding of java basics and syntax. 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.
A junior developer wrote the following code to calculate the sum of an array:
int[] numbers = {1, 2, 3, 4, 5};
int sum = 0;
for (int i = 1; i <= numbers.length; i++) {
sum += numbers[i];
}
System.out.println("Sum: " + sum);
The developer expects the output to be 15, but the program throws an exception. What is the root cause and the correct fix?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Change to: for (int i = 0; i < numbers.length; i++)
The loop starts at index 1 instead of 0, and goes up to index numbers.length (which is 5), but valid indices are 0-4. So accessing numbers[5] throws ArrayIndexOutOfBoundsException. The fix is to start at i=0 and continue while i < numbers.length. Option C is correct. Option A is wrong because the condition is still <= causing out-of-bounds. Option B changes step but still wrong start. Option D is for enhanced for loop, but the original is traditional for loop; the fix should maintain traditional loop style.
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.
✗
Change to enhanced for loop: for (int num : numbers) sum += num;
Why it's wrong here
This would work but does not directly fix the original loop; the question asks for fix of the given loop.
✓
Change to: for (int i = 0; i < numbers.length; i++)
Why this is correct
Correct start and condition.
Related concept
Read the scenario before looking for a memorised answer.
✗
Change to: for (int i = 1; i < numbers.length; i += 2)
Why it's wrong here
This skips elements and still starts at 1.
✗
Change to: for (int i = 0; i <= numbers.length; i++)
Why it's wrong here
Still out of bounds because <= includes length which is invalid index.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 1Z0-811 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Java Basics and Syntax — This question tests Java Basics and Syntax — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Change to: for (int i = 0; i < numbers.length; i++) — The loop starts at index 1 instead of 0, and goes up to index numbers.length (which is 5), but valid indices are 0-4. So accessing numbers[5] throws ArrayIndexOutOfBoundsException. The fix is to start at i=0 and continue while i < numbers.length. Option C is correct. Option A is wrong because the condition is still <= causing out-of-bounds. Option B changes step but still wrong start. Option D is for enhanced for loop, but the original is traditional for loop; the fix should maintain traditional loop style.
What should I do if I get this 1Z0-811 question wrong?
Identify which 1Z0-811 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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