- A
System.arraycopy(source, 0, dest, 0, 3);
Correct parameters.
- B
System.arraycopy(source, 0, dest, 0, 5);
Why wrong: Length 5 exceeds dest length.
- C
System.arraycopy(source, 1, dest, 0, 3);
Why wrong: sourcePos should be 0, not 1.
- D
System.arraycopy(source, 0, dest, 1, 3);
Why wrong: destPos should be 0, not 1.
Question 455 of 509
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.
Given 'int[] source = {1,2,3,4,5};' and 'int[] dest = new int[3];' which code correctly copies the first three elements from source to dest using System.arraycopy?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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
✓
System.arraycopy(source, 0, dest, 0, 3);
Option A is correct because `System.arraycopy(source, 0, dest, 0, 3)` copies exactly three elements starting from index 0 of the source array to index 0 of the destination array, matching the requirement. The `length` argument (3) specifies the number of array elements to copy, and the destination array has a capacity of 3, so no `ArrayIndexOutOfBoundsException` occurs.
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.
- ✓
System.arraycopy(source, 0, dest, 0, 3);
Why this is correct
Correct parameters.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
System.arraycopy(source, 0, dest, 0, 5);
Why it's wrong here
Length 5 exceeds dest length.
- ✗
System.arraycopy(source, 1, dest, 0, 3);
Why it's wrong here
sourcePos should be 0, not 1.
- ✗
System.arraycopy(source, 0, dest, 1, 3);
Why it's wrong here
destPos should be 0, not 1.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Oracle often tests the misconception that the `length` parameter refers to the total size of the destination array rather than the number of elements to copy, leading candidates to choose option B.
Detailed technical explanation
How to think about this question
`System.arraycopy` is a native method that performs a low-level, type-checked, and potentially faster block copy using `memmove`-like semantics, handling overlapping regions correctly. The method signature is `public static void arraycopy(Object src, int srcPos, Object dest, int destPos, int length)`, and it throws `NullPointerException` if any array is null, `IndexOutOfBoundsException` if any index or length is invalid, and `ArrayStoreException` if a type mismatch occurs. In real-world scenarios, this method is preferred over manual loops for performance-critical bulk array copying, such as in buffer resizing or collection implementations.
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 — study guide chapter
Learn the concepts, then practise the questions
- →
Arrays and Methods practice questions
Targeted practice on this topic area only
- →
All 1Z0-811 questions
509 questions across all exam domains
- →
Oracle Java Foundations 1Z0-811 study guide
Full concept coverage aligned to exam objectives
- →
1Z0-811 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related 1Z0-811 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
What is Java practice questions
Practise 1Z0-811 questions linked to What is Java.
Java Basics and Syntax practice questions
Practise 1Z0-811 questions linked to Java Basics and Syntax.
Primitives, Strings and Operators practice questions
Practise 1Z0-811 questions linked to Primitives, Strings and Operators.
Control Flow and Loops practice questions
Practise 1Z0-811 questions linked to Control Flow and Loops.
Arrays and Methods practice questions
Practise 1Z0-811 questions linked to Arrays and Methods.
Object-Oriented Programming practice questions
Practise 1Z0-811 questions linked to Object-Oriented Programming.
Exception Handling and Development Tools practice questions
Practise 1Z0-811 questions linked to Exception Handling and Development Tools.
1Z0-811 fundamentals practice questions
Practise 1Z0-811 questions linked to 1Z0-811 fundamentals.
1Z0-811 scenario practice questions
Practise 1Z0-811 questions linked to 1Z0-811 scenario.
1Z0-811 troubleshooting practice questions
Practise 1Z0-811 questions linked to 1Z0-811 troubleshooting.
Practice this exam
Start a free 1Z0-811 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this 1Z0-811 question test?
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: System.arraycopy(source, 0, dest, 0, 3); — Option A is correct because `System.arraycopy(source, 0, dest, 0, 3)` copies exactly three elements starting from index 0 of the source array to index 0 of the destination array, matching the requirement. The `length` argument (3) specifies the number of array elements to copy, and the destination array has a capacity of 3, so no `ArrayIndexOutOfBoundsException` occurs.
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: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More 1Z0-811 practice questions
- A developer is troubleshooting a performance issue in a reporting application. A nested loop iterates over a large datas…
- A developer writes: boolean b = !true && false; What is the value of b?
- Given: int a = 10; int b = 20; boolean flag = a++ > 10 && ++b > 20; What are the values of a and b after execution?
- What is the value of the expression (10 > 5) && (3 < 2)?
- Which primitive data type should be used to store a single character?
- A developer writes: for(int i=0; i<10; i++) { if(i%2==0) continue; System.out.print(i); }. What is the output?
Last reviewed: Jun 30, 2026
This 1Z0-811 practice question is part of Courseiva's free Oracle certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 1Z0-811 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.