The correct answer is that overloading with `public void print(String[] s)` and `public void print(String... s)` causes a compilation error. This happens because Java treats varargs as an array at the bytecode level, so both methods have the identical signature `print(String[])` after type erasure, making them ambiguous to the compiler. On the Oracle Java Foundations 1Z0-811 exam, this tests your understanding that varargs is syntactic sugar for an array, not a distinct type — a common trap where students assume the compiler can distinguish between a fixed array parameter and a variable-length argument list. The key distinction is that while you can call a varargs method with an array, you cannot overload it with an explicit array parameter of the same element type. Remember the mnemonic: "Varargs is an array in disguise — overloading them is a compile-time surprise."
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.
Exhibit
javac Test.java
Test.java:5: error: reference to print is ambiguous
print(null);
^
both method print(String[]) in Test and method print(String...) in Test match
Refer to the exhibit. Which overloaded methods cause this compilation error?
javac Test.java
Test.java:5: error: reference to print is ambiguous
print(null);
^
both method print(String[]) in Test and method print(String...) in Test match
A
public void print(String s) and public void print(String[] s)
Why wrong: null matches both String and String[], but String is not an array; compiler chooses most specific? Actually ambiguous? Not in this case because String is not an array. The error shows String[] and String... conflict.
B
public void print(String s) and public void print(String... s)
Why wrong: These are not ambiguous because String s is not an array.
C
public void print(String[] s) and public void print(String... s)
Both match when passing null, causing ambiguity.
D
public void print(Object... o) and public void print(String... s)
Why wrong: Multiple varargs are not typically ambiguous with null as null matches both, but compiler error would mention both varargs? Actually it would be ambiguous too, but the exhibit specifically shows String[] and String... . So B is correct.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
public void print(String[] s) and public void print(String... s)
Option C is correct because Java does not allow overloading methods that differ only by the use of a varargs parameter and an array parameter of the same type. Both `public void print(String[] s)` and `public void print(String... s)` have the same method signature after erasure — they both accept a `String[]` at the bytecode level — causing a compilation error due to ambiguity.
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.
✗
public void print(String s) and public void print(String[] s)
Why it's wrong here
null matches both String and String[], but String is not an array; compiler chooses most specific? Actually ambiguous? Not in this case because String is not an array. The error shows String[] and String... conflict.
✗
public void print(String s) and public void print(String... s)
Why it's wrong here
These are not ambiguous because String s is not an array.
✓
public void print(String[] s) and public void print(String... s)
Why this is correct
Both match when passing null, causing ambiguity.
Related concept
Read the scenario before looking for a memorised answer.
✗
public void print(Object... o) and public void print(String... s)
Why it's wrong here
Multiple varargs are not typically ambiguous with null as null matches both, but compiler error would mention both varargs? Actually it would be ambiguous too, but the exhibit specifically shows String[] and String... . So B is correct.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates mistakenly think varargs and arrays are distinct types for overloading, but Java treats them identically after compilation, so defining both `print(String[])` and `print(String...)` causes a duplicate method error.
Trap categories for this question
Command / output trap
null matches both String and String[], but String is not an array; compiler chooses most specific? Actually ambiguous? Not in this case because String is not an array. The error shows String[] and String... conflict.
Detailed technical explanation
How to think about this question
Under the hood, Java treats varargs (`String... s`) as syntactic sugar for an array (`String[] s`). When both a fixed-array method and a varargs method with the same element type are defined, the compiler sees two methods with identical erased signatures — `print(String[])` — leading to a duplicate method error. This is specified in JLS §8.4.2, which states that two methods cannot have the same name and parameter types after erasure. In real-world code, this often arises when refactoring from an array parameter to varargs without removing the original method.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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 — 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: public void print(String[] s) and public void print(String... s) — Option C is correct because Java does not allow overloading methods that differ only by the use of a varargs parameter and an array parameter of the same type. Both `public void print(String[] s)` and `public void print(String... s)` have the same method signature after erasure — they both accept a `String[]` at the bytecode level — causing a compilation error due to ambiguity.
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.
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 →
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.
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.