❮ Previous Quiz
Next Quiz ❯
Java 8 introduced several new features and enhancements to the programming language. This blog post presents a Java 8 quiz comprising 40+ multiple-choice questions.
This quiz aims to assess your understanding of the new features and concepts introduced in Java 8, such as Java 8 Lambda Expressions, Java 8 Functional Interfaces, Java 8 Method References, and Java 8 Stream API.
Learn and Master Java Programming: Learn Java Programming with Examples.
Learn everything about Java 8 features: Java 8 Tutorial and Examples.
Check out 100+ quiz questions: 100+ Quiz Questions to Test Your Java, Spring Boot, Microservices, Hibernate, REST API Skills.
Let's put your Java 8 knowledge to the test!
YouTube Video - Java 8 Quiz
Subscribe to my YouTube channel to learn more: https://www.youtube.com/@javaguides.
1. What is a lambda expression in Java?
a) A way to define anonymous methods
b) A method with no return type
c) A method that is only available in interfaces
d) A class that implements an interface
2. Which Java version introduced lambda expressions?
a) Java 6
b) Java 7
c) Java 8
d) Java 9
3. What is the Stream API in Java?
a) A feature for handling files in Java
b) A way to process sequences of elements in a functional style
c) A method for sorting arrays
d) An interface for input/output operations
4. Which method is used to create a stream from a collection in Java?
a) stream()
b) createStream()
c) asStream()
d) toStream()
5. What does the Optional class in Java represent?
a) A way to represent null values
b) A container that may or may not contain a value
c) A collection of elements
d) A method that returns multiple values
6. Which functional interface is commonly used with lambda expressions in Java?
a) Runnable
b) Callable
c) Function
d) Serializable
7. What is the syntax for a basic lambda expression in Java?
a) (parameters) -> expression
b) (expression) -> parameters
c) {expression} -> parameters
d) (parameters) => expression
8. Can lambda expressions have multiple parameters?
a) Yes, they can have multiple parameters
b) No, they can only have one parameter
c) Yes, but only if they return a value
d) No, they cannot have any parameters
9. What does the Stream API's filter() method do?
a) It filters elements of a stream based on a predicate
b) It maps each element to a collection
c) It reduces elements of a stream
d) It sorts elements in a stream
10. What is the purpose of the forEach() method in the Stream API?
a) To count the elements in the stream
b) To iterate over each element in the stream and perform an action
c) To remove duplicates from the stream
d) To sort the elements in the stream
11. What is a default method in an interface in Java?
a) A method with no implementation
b) A method that must be overridden
c) A method with a default implementation in the interface
d) A method that is called first in a class
12. Which method is used to check if a stream is empty?
a) isEmpty()
b) noneMatch()
c) count()
d) allMatch()
13. What is the purpose of the Predicate functional interface in Java?
a) To return an object
b) To perform an action on an object
c) To test a condition on an object
d) To create an object
14. Can lambda expressions be used with the Comparator interface?
a) Yes, lambda expressions can be used with Comparator
b) No, lambda expressions cannot be used with Comparator
c) Yes, but only with Integer objects
d) No, they are only used with Function interface
15. What is the use of the Optional class in Java?
a) To handle collections of data
b) To represent the presence or absence of a value
c) To throw exceptions
d) To perform arithmetic operations
16. Which method is used to retrieve a value from an Optional if it is present?
a) getValue()
b) retrieve()
c) get()
d) fetch()
17. What is the difference between map() and flatMap() in the Stream API?
a) map() transforms elements, flatMap() flattens nested structures
b) map() filters elements, flatMap() maps them
c) map() reduces elements, flatMap() sorts them
d) There is no difference between map() and flatMap()
18. Can streams be parallelized in Java?
a) Yes, using the parallelStream() method
b) No, streams cannot be parallelized
c) Yes, but only for numeric streams
d) No, only arrays can be parallelized
19. What is the Collectors class in the Stream API used for?
a) To collect elements from a stream into a collection
b) To map elements in a stream
c) To filter elements in a stream
d) To sort elements in a stream
20. Which method in the Optional class is used to return a default value if the value is absent?
a) orElse()
b) ifPresent()
c) getOrDefault()
d) fetch()
21. Which new date and time API was introduced in Java 8?
a) java.util.Date
b) java.sql.Date
c) java.time
d) java.date
22. What does the map() method do in the Stream API?
a) It transforms each element in the stream
b) It maps elements to a new collection
c) It reduces elements to a single value
d) It filters elements in the stream
23. Which method is used to check if all elements in a stream match a given predicate?
a) allMatch()
b) anyMatch()
c) noneMatch()
d) matchesAll()
24. Can streams in Java be reused?
a) Yes, streams can be reused multiple times
b) No, streams cannot be reused once they are consumed
c) Yes, but only parallel streams
d) Yes, if they are collected first
25. Which method in the Stream API is used to remove duplicate elements?
a) filter()
b) distinct()
c) unique()
d) removeDuplicates()
26. Which method is used to sort elements in a stream?
a) sort()
b) order()
c) sorted()
d) arrange()
Answer:
c) sorted()
Explanation:
The sorted() method in the Stream API is used to sort the elements in a stream either in natural order or using a custom comparator.
27. Which method in the Stream API is used to combine elements of a stream into a single result?
a) map()
b) reduce()
c) combine()
d) collect()
Answer:
b) reduce()
Explanation:
The reduce() method in the Stream API is used to combine elements of a stream into a single result using an accumulator function.
28. What does the findFirst() method do in a stream?
a) It finds the first element in the stream and returns it
b) It finds the first element matching a condition
c) It returns the first element or throws an exception
d) It returns the first non-null element
Answer:
a) It finds the first element in the stream and returns it
Explanation:
The findFirst() method in the Stream API finds the first element in a stream and returns it wrapped in an Optional if it exists.
29. Which method is used to get the count of elements in a stream?
a) size()
b) count()
c) getCount()
d) length()
Answer:
b) count()
Explanation:
The count() method in the Stream API returns the number of elements in the stream.
30. Can you perform parallel processing with the Stream API in Java?
a) Yes, using parallelStream()
b) No, the Stream API does not support parallel processing
c) Yes, but only with List collections
d) No, only arrays support parallel processing
Answer:
a) Yes, using parallelStream()
Explanation:
You can perform parallel processing with the Stream API in Java using the parallelStream() method, which processes elements concurrently on multiple cores.
31. What is the difference between findFirst() and findAny() in the Stream API?
a) findFirst() returns the first element, findAny() returns any element
b) findFirst() is for sequential streams, findAny() is for parallel streams
c) findFirst() returns a non-null element, findAny() returns any element
d) There is no difference
Answer:
a) findFirst() returns the first element, findAny() returns any element
Explanation:
findFirst() returns the first element in a stream, while findAny() returns any element in the stream, potentially more efficient in parallel streams.
32. Which method is used to skip a given number of elements in a stream?
a) drop()
b) skip()
c) omit()
d) jump()
Answer:
b) skip()
Explanation:
The skip() method in the Stream API skips the first n elements and returns a stream containing the remaining elements.
33. Which new interface was introduced in Java 8 to represent a function that takes no arguments and returns a result?
a) Function
b) Supplier
c) Consumer
d) Predicate
Answer:
b) Supplier
Explanation:
The Supplier interface was introduced in Java 8 to represent a function that takes no arguments and returns a result.
34. Can lambda expressions be used with the Runnable interface?
a) Yes, lambda expressions can be used with Runnable
b) No, lambda expressions cannot be used with Runnable
c) Yes, but only for single-threaded applications
d) No, lambda expressions are only used with functional interfaces
Answer:
a) Yes, lambda expressions can be used with Runnable
Explanation:
Lambda expressions can be used with the Runnable interface to simplify the syntax of creating threads or tasks in Java.
35. What is the main purpose of the Stream API in Java?
a) To perform I/O operations
b) To handle exceptions
c) To process collections of data in a functional style
d) To create multi-threaded applications
Answer:
c) To process collections of data in a functional style
Explanation:
The Stream API in Java is designed to process collections of data in a functional style, enabling operations like filtering, mapping, and reducing.
36. What is the purpose of the peek() method in the Stream API?
a) To modify the elements of a stream
b) To view elements of a stream without modifying them
c) To remove elements from a stream
d) To sort the elements of a stream
Answer:
b) To view elements of a stream without modifying them
Explanation:
The peek() method is used to view elements of a stream without modifying them. It is often used for debugging purposes.
37. Which method is used to limit the number of elements in a stream?
a) limit()
b) reduce()
c) cap()
d) filter()
Answer:
a) limit()
Explanation:
The limit() method is used to limit the number of elements in a stream to the specified size.
38. What is the difference between a stream() and a parallelStream() in Java?
a) stream() is faster than parallelStream()
b) parallelStream() processes elements in parallel
c) stream() uses more memory
d) parallelStream() is only for arrays
Answer:
b) parallelStream() processes elements in parallel
Explanation:
The parallelStream() method processes elements in parallel, potentially improving performance on multi-core processors.
39. Which method is used to find the first element in a stream?
a) findFirst()
b) firstElement()
c) getFirst()
d) find()
Answer:
a) findFirst()
Explanation:
The findFirst() method is used to find the first element in a stream and returns an Optional containing the element if it exists.
40. Can lambda expressions be used to create threads in Java?
a) Yes, using the Runnable interface
b) Yes, using the Callable interface
c) No, lambda expressions cannot be used to create threads
d) Yes, using the Supplier interface
Answer:
a) Yes, using the Runnable interface
Explanation:
Lambda expressions can be used to create threads in Java by passing them to the Runnable interface, which is then passed to a Thread.
Conclusion
Congratulations on completing the Java 8 quiz! We hope it challenged your knowledge and provided valuable insights into the new features and concepts introduced in Java 8. Understanding the enhancements in Java 8 is crucial for writing modern and efficient Java code.Learn everything about Java 8 features: Java 8 Tutorial and Examples.
Check out 100+ quiz questions: 100+ Quiz Questions to Test Your Java, Spring Boot, Microservices, Hibernate, REST API Skills.
Keep learning, practicing, and embracing the power of Java 8 in your programming journey!
❮ Previous Quiz
Next Quiz ❯
Comments
Post a Comment
Leave Comment