Quick Answer
The answer is 1. This occurs because Java uses pass-by-value for all method parameters, including array references, meaning the local variable `arr` inside the `change` method holds a copy of the original reference; reassigning that copy to a new array object has no effect on the original array in `main`. This concept of method parameter array reassignment is a classic trap on the Oracle Java Foundations 1Z0-811 exam, testing your understanding that while you can modify the contents of an array through its reference, you cannot change which array the caller’s variable points to. A common mistake is assuming the reassignment inside the method updates the original, but the local variable simply points to a new object and then goes out of scope. Remember the memory tip: “You can change the house’s furniture, but you cannot move the house itself.”
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 the code:
public class Test {
public static void change(int[] arr) {arr = new int[]{10, 20};
}
public static void main(String[] args) {int[] arr = {1, 2}; change(arr); System.out.println(arr[0]);
} }
What is the output?
1
The method creates a new array and assigns it to the local parameter, but this assignment does not change the caller's reference, so arr[0] remains 1.
10
Why wrong: 10 is from the new array created inside the method, but it is not reflected in the caller's scope.
20
Why wrong: Similar to B.
Compilation error
Why wrong: The code compiles and runs without error.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
1
Option A is correct because in Java, array references are passed by value. Inside the `change` method, the local variable `arr` is reassigned to a new array, but this does not affect the original array reference in `main`. Therefore, `arr[0]` in `main` still refers to the original array element `1`.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
1
Why this is correct
The method creates a new array and assigns it to the local parameter, but this assignment does not change the caller's reference, so arr[0] remains 1.
Related concept
Read the scenario before looking for a memorised answer.
10
Why it's wrong here
10 is from the new array created inside the method, but it is not reflected in the caller's scope.
20
Why it's wrong here
Similar to B.
Compilation error
Why it's wrong here
The code compiles and runs without error.
Common exam traps
Oracle often tests the distinction between modifying an object's state versus reassigning a reference, and the trap here is that candidates mistakenly believe reassigning the parameter inside the method will change the original array reference in the caller.
Trap categories for this question
Similar concept trap
Similar to B.
Detailed technical explanation
In Java, all parameters are passed by value, meaning the method receives a copy of the reference. Reassigning the local reference to a new object does not affect the caller's reference. This is a common source of confusion, especially when modifying object state versus reassigning references. In real-world scenarios, this behavior is critical when designing methods that should modify collections or arrays in place.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
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FAQ
Arrays and Methods — This question tests Arrays and Methods — Read the scenario before looking for a memorised answer..
The correct answer is: 1 — Option A is correct because in Java, array references are passed by value. Inside the `change` method, the local variable `arr` is reassigned to a new array, but this does not affect the original array reference in `main`. Therefore, `arr[0]` in `main` still refers to the original array element `1`.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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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.
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