Quick Answer
The answer is Hello. This occurs because strings in Java are immutable, meaning once a String object is created, its value cannot be changed. When the concat() method is called on the variable s, it returns a brand new String object containing "Hello World", but that new object is not assigned to any variable—the original String s still points to "Hello". The System.out.println(s) statement therefore prints the unchanged original. On the Oracle Java Foundations 1Z0-811 exam, this question tests your understanding of immutability and the common trap of forgetting to reassign the result of methods like concat(), replace(), or toUpperCase(). A frequent exam scenario shows a junior developer assuming the original String is modified in place. To avoid this pitfall, remember the memory tip: "Strings never change—they just create new copies." Always assign the result back to a variable if you want to keep the modified value.
This 1Z0-811 practice question tests your understanding of object-oriented programming. 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 writes a method that attempts to modify a String: public void update() { String s = "Hello"; s.concat(" World"); System.out.println(s); } What will be printed when update() is called?
Hello World
Why wrong: concat() returns a new String, but the result is not assigned to s, so s remains "Hello".
Hello World (no space)
Why wrong: The concat method does add the space, but the original string is unchanged.
Compilation error
Why wrong: The code compiles fine; it just doesn't update s.
Hello
Correct. Strings are immutable; concat() does not modify the original string.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Hello
Strings are immutable in Java. The concat() method returns a new String but the original object remains unchanged because the result is not assigned.
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.
Hello World
Why it's wrong here
concat() returns a new String, but the result is not assigned to s, so s remains "Hello".
Hello World (no space)
Why it's wrong here
The concat method does add the space, but the original string is unchanged.
Compilation error
Why it's wrong here
The code compiles fine; it just doesn't update s.
Hello
Why this is correct
Correct. Strings are immutable; concat() does not modify the original string.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
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
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.
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
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.
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FAQ
Object-Oriented Programming — This question tests Object-Oriented Programming — Read the scenario before looking for a memorised answer..
The correct answer is: Hello — Strings are immutable in Java. The concat() method returns a new String but the original object remains unchanged because the result is not assigned.
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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 23, 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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