Java MCQs – Java 8 Features

This article provides a comprehensive overview of Java 8’s key features through a series of top multiple-choice questions (MCQs). It covers fundamental concepts like lambda expressions and functional interfaces, as well as advanced topics such as CompletableFutures, parallel streams, and method references. Whether you’re a seasoned Java developer looking to sharpen your skills or someone exploring the world of Java for the first time, these MCQs will help you grasp the essence of Java 8 and its capabilities, making you a more proficient and confident Java programmer.

Java 8, released in 2014, marked a significant milestone in the evolution of the Java programming language. It introduced a wide array of features and enhancements that transformed the way developers write Java code. From the introduction of lambda expressions and functional interfaces to the powerful Streams API and the modern Date and Time API, Java 8 brought functional programming and improved data manipulation capabilities to the language.

1.) What is the primary purpose of lambda expressions in Java?

A) To create anonymous classes
B) To define abstract methods
C) To write anonymous functions
D) To declare variables

Answer: Option C

Explanation: Lambda expressions allow you to write anonymous functions.

2.) Which annotation is used to define a functional interface in Java?

A) @FunctionalAnnotation
B) @Interface
C) @Functional
D) @FunctionalInterface

Answer: Option D

Explanation: @FunctionalInterface is used to define functional interfaces.

3.) What is the purpose of default methods in Java interfaces?

A) To define abstract methods
B) To provide default implementations
C) To create new interfaces
D) To force implementation in subclasses

Answer: Option B

Explanation: Default methods provide default implementations in interfaces.

4.) Which Java package provides the Streams API for collection manipulation?


Answer: Option A

Explanation: The Streams API is in the package.

5.) What is the purpose of method references in Java?

A) To create new methods
B) To call methods indirectly
C) To define abstract methods
D) To create anonymous classes

Answer: Option B

Explanation: Method references are used to call methods indirectly.

6.) Which functional interface represents a function that takes no arguments and returns no result?

A) Function
B) Consumer
C) Supplier
D) Predicate

Answer: Option C

Explanation: Supplier represents a function with no arguments and no result.

7.) What is the primary advantage of the Optional class in Java 8?

A) It simplifies method chaining.
B) It reduces the number of exceptions.
C) It avoids null pointer exceptions.
D) It allows for mutable objects.

Answer: Option C

Explanation: The Optional class helps avoid null pointer exceptions.

8.) In Java 8, which package contains the modern Date and Time API?

A) java.util
B) java.time
D) java.calendar

Answer: Option B

Explanation: The modern Date and Time API is in the java.time package.

9.) Which JavaScript engine was introduced in Java 8 for improved performance?

A) Rhino
B) V8
C) Nashorn
D) SpiderMonkey

Answer: Option C

Explanation: Java 8 introduced the Nashorn JavaScript engine.

10.) What is the primary use of CompletableFuture in Java 8?

A) To create thread pools
B) To work with asynchronous and concurrent code
C) To provide default implementations for interfaces
D) To manage file streams

Answer: Option B

Explanation: CompletableFuture is used to work with asynchronous and concurrent code.

Leave a Reply

Your email address will not be published. Required fields are marked *