Quick Answer
The correct choice is the assignment `int i = 10L;` because it requires an explicit cast to compile. This is a textbook example of an explicit cast for narrowing conversion, where a 64-bit `long` literal is being forced into a 32-bit `int` variable. In Java, narrowing primitive conversions like this are not allowed implicitly since they risk data loss; the compiler demands a cast, such as `(int)`, to acknowledge the potential precision loss. On the Oracle Java Foundations 1Z0-811 exam, this concept frequently appears to test your understanding of type compatibility and the distinction between widening and narrowing conversions. A common trap is assuming that integer literals with an `L` suffix can automatically fit into smaller types, but the compiler strictly enforces the size hierarchy. To remember this, think: “Widening is automatic, narrowing requires a cast—long to int is a squeeze, not a fit.”
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.
Which assignment requires an explicit cast to compile?
int i = 10L;
Correct. long to int needs explicit cast.
double d = 10;
Why wrong: Incorrect. int to double is widening, no cast needed.
long l = 10;
Why wrong: Incorrect. int to long is widening, no cast needed.
float f = 10.5f;
Why wrong: Incorrect. float literal, no cast needed.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
int i = 10L;
Option A requires an explicit cast because it assigns a `long` literal (10L) to an `int` variable. In Java, `long` is a 64-bit type and `int` is 32-bit, so this is a narrowing primitive conversion that loses precision and must be explicitly cast with `(int)`. Without the cast, the compiler rejects it as a possible lossy conversion.
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.
int i = 10L;
Why this is correct
Correct. long to int needs explicit cast.
Related concept
Read the scenario before looking for a memorised answer.
double d = 10;
Why it's wrong here
Incorrect. int to double is widening, no cast needed.
long l = 10;
Why it's wrong here
Incorrect. int to long is widening, no cast needed.
float f = 10.5f;
Why it's wrong here
Incorrect. float literal, no cast needed.
Common exam traps
Oracle often tests the misconception that any numeric literal with a suffix (like `L` or `f`) automatically requires a cast, but the trap here is that only narrowing conversions (e.g., `long` to `int`) need explicit casting, not widening ones or assignments of the same type.
Detailed technical explanation
Under the hood, Java's type conversion rules are defined by JLS §5.1.2 (widening) and §5.1.3 (narrowing). Widening conversions preserve magnitude and never lose information, so they are implicit. Narrowing conversions, like `long` to `int`, truncate the high-order bits, potentially losing data, hence requiring an explicit cast. A real-world scenario is when reading sensor data as `long` timestamps but needing to store them in an `int` array for memory efficiency—this forces the programmer to acknowledge the truncation risk.
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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Java Basics and Syntax — study guide chapter
Learn the concepts, then practise the questions
Java Basics and Syntax 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
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 1Z0-811 questions linked to What is Java.
Practise 1Z0-811 questions linked to Java Basics and Syntax.
Practise 1Z0-811 questions linked to Primitives, Strings and Operators.
Practise 1Z0-811 questions linked to Control Flow and Loops.
Practise 1Z0-811 questions linked to Arrays and Methods.
Practise 1Z0-811 questions linked to Object-Oriented Programming.
Practise 1Z0-811 questions linked to Exception Handling and Development Tools.
Practise 1Z0-811 questions linked to 1Z0-811 fundamentals.
Practise 1Z0-811 questions linked to 1Z0-811 scenario.
Practise 1Z0-811 questions linked to 1Z0-811 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Java Basics and Syntax — This question tests Java Basics and Syntax — Read the scenario before looking for a memorised answer..
The correct answer is: int i = 10L; — Option A requires an explicit cast because it assigns a `long` literal (10L) to an `int` variable. In Java, `long` is a 64-bit type and `int` is 32-bit, so this is a narrowing primitive conversion that loses precision and must be explicitly cast with `(int)`. Without the cast, the compiler rejects it as a possible lossy conversion.
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.
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 →
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.