Java Date & Time API - Practice Questions 2026

Mastering the Java Date and Time API (java. time package) is a critical requirement for modern Java developers. Since its introduction in Java 8, this API has become the industry standard, replacing the older, thread-unsafe Date and Calendar classes. This course is designed to provide a comprehensive testing ground for developers who want to validate their knowledge and ensure they are production-ready.Why Serious Learners Choose These Practice ExamsThese exams are crafted to simulate real-world coding challenges and certification-style questions. Unlike basic quizzes, our question bank focuses on the nuances of temporal arithmetic, timezone complexities, and formatting patterns. By choosing this course, you ensure that you are not just memorizing syntax, but understanding the underlying logic of immutable date-time objects.Course StructureOur practice tests are organized into a logical progression to help you build confidence as you move from fundamentals to expert-level scenarios.Basics / Foundations: This section covers the fundamental classes such as LocalDate, LocalTime, and LocalDateTime. You will be tested on object creation, basic getters, and understanding the immutability of these classes.Core Concepts: Here, we dive into periods and durations. You will learn to distinguish between date-based and time-based amounts and how to manipulate them using the plus and minus methods.Intermediate Concepts: This module focuses on the Instant class and ZonedDateTime. Handling Unix timestamps and understanding how to transition between different geographical time zones is a key focus here.Advanced Concepts: We explore TemporalAdjusters and the DateTimeFormatter class. You will practice finding the "next Tuesday" or "last day of the month" and creating custom patterns for parsing and formatting strings.Real-world Scenarios: These questions place you in a professional environment. You will solve problems related to daylight saving time transitions, database persistence, and calculating age or tenure across different locales.Mixed Revision / Final Test: A comprehensive mock exam that pulls from all categories to test your speed, accuracy, and readiness for a technical interview or certification.Sample Practice QuestionsQuestion 1Which of the following is the correct way to add 2 months to a LocalDate object named "today" while ensuring the result is stored in a new variable?Option 1: today. plusMonths(2);Option 2: LocalDate future = today. addMonths(2);Option 3: LocalDate future = today. plus(2, ChronoUnit. MONTHS);Option 4: today. setMonth(today. getMonth() + 2);Option 5: LocalDate future = new LocalDate(today). plusMonths(2);Correct Answer: Option 3Correct Answer Explanation: The java. time API is immutable. The . plus(long, TemporalUnit) method is a generic way to add time and returns a new object. Option 3 correctly assigns the result to a new variable.Wrong Answers Explanation:Option 1: While the method call is valid, it ignores the return value. Since LocalDate is immutable, "today" remains unchanged, and the result is lost.Option 2: There is no method named "addMonths" in the LocalDate class; the correct naming convention is "plusMonths".Option 4: LocalDate does not have setter methods because it is immutable. Attempting to "set" a value will result in a compilation error.Option 5: LocalDate has a private constructor and cannot be instantiated with the "new" keyword. It uses factory methods like . of() or . now().Question 2What will be the result of the following code snippet?Period period = Period. ofDays(5);Duration duration = Duration. ofDays(5);System. out. println(period. equals(duration));Option 1: trueOption 2: falseOption 3: Compilation ErrorOption 4: Runtime ExceptionOption 5: true if the system clock is set to UTCCorrect Answer: Option 2Correct Answer Explanation: Period and Duration are different types. Period is used for date-based amounts (Years, Months, Days), while Duration is used for time-based amounts (Seconds, Nanoseconds). Even though they represent the same conceptual length of time, the . equals() method in Java checks for type compatibility. Since they are different classes, it returns false.Wrong Answers Explanation:Option 1: The . equals() method returns false because a Period object is never equal to a Duration object in the Java API.Option 3: The code is syntactically correct and will compile without any issues.Option 4: No exceptions are thrown during this comparison; it is a standard logical check.Option 5: The system timezone or clock has no impact on the comparison of Period and Duration objects.Course FeaturesWelcome to the best practice exams to help you prepare for your Java Date & Time API skills. This course offers:You can retake the exams as many times as you want to achieve 100% mastery.This is a huge original question bank designed by Java experts.You get support from instructors if you have questions regarding any specific scenario.Each question has a detailed explanation to ensure you understand the "why" behind the answer.Mobile-compatible with the Udemy app so you can study on the go.30-days money-back guarantee if you are not satisfied with the course content.We hope that by now you are convinced! And there are a lot more questions inside the course.