The correct answer is that the code tries to access index 5 of a 5-element array. This is because Java arrays are zero-indexed, meaning a 5-element array has valid indices from 0 to 4, so attempting to use the array’s length value—5—as an index directly causes an ArrayIndexOutOfBoundsException at runtime. This classic off-by-one error is a frequent trap on the Oracle Java Foundations 1Z0-811 exam, where it tests your understanding of array bounds and loop conditions. The exam often presents code that mistakenly uses `array.length` as the upper limit in a loop or direct access, expecting you to recognize that the last valid index is always `length - 1`. A simple memory tip: remember that Java arrays start counting at zero, so the index number is always one less than the element’s position—think “zero is the hero, length is the limit you must subtract.”
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.
Exhibit
$ java Test
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5
at Test.main(Test.java:3)
Refer to the exhibit. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The code tries to access index 5 of a 5-element array.
Option C is correct because Java arrays are zero-indexed, meaning a 5-element array has valid indices 0 through 4. Accessing index 5 attempts to read beyond the array bounds, causing an ArrayIndexOutOfBoundsException at runtime. This is a classic off-by-one error where the code mistakenly uses the array length as the index.
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.
✗
The array has 6 elements.
Why it's wrong here
Exception says length 5, not 6.
✗
The code tries to access index 4 of a 5-element array.
Why it's wrong here
Index 4 is valid, would not cause exception.
✓
The code tries to access index 5 of a 5-element array.
Why this is correct
Indices 0-4 are valid; index 5 is out of bounds.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The code has a syntax error.
Why it's wrong here
Syntax error would prevent compilation, not produce this exception.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Oracle often tests the off-by-one error where candidates mistakenly think the last valid index is the array length (e.g., 5) instead of length-1 (e.g., 4), leading them to choose option B or misidentify the array size.
Detailed technical explanation
How to think about this question
In Java, arrays are objects with a fixed length determined at creation, and the length field stores the number of elements. The JVM performs bounds checking on every array access; if the index is negative or >= length, it throws an ArrayIndexOutOfBoundsException. This is a common pitfall when iterating with a loop that uses <= instead of <, or when confusing the length with the last valid index.
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.
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: The code tries to access index 5 of a 5-element array. — Option C is correct because Java arrays are zero-indexed, meaning a 5-element array has valid indices 0 through 4. Accessing index 5 attempts to read beyond the array bounds, causing an ArrayIndexOutOfBoundsException at runtime. This is a classic off-by-one error where the code mistakenly uses the array length as the index.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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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