Java 8

Question 1

What is a lambda expression in Java 8?

Answer 1

A concise way to represent an anonymous function.

Question 2

What is the purpose of the Stream API in Java 8?

Answer 2

To manipulate collections of data in a functional style.

Question 3

Which annotation is used to declare a functional interface in Java 8?

Answer 3

@FunctionalInterface

Question 4

How many types of method references are there in Java 8?

Answer 4

4
(Exp.: There are four types of method references in Java 8: static method references, instance method references of a particular object, instance method references of an arbitrary object, and constructor references.)

Question 5

What is the default method in an interface in Java 8?

Answer 5

A method that is automatically inherited by implementing classes.
(Exp.: A default method in an interface is automatically inherited by implementing classes and can be overridden if needed.)

Question 6

What is the purpose of the Optional class in Java 8?

Answer 6

To represent nullable values safely and avoid NullPointerExceptions.

Question 7

What is the main advantage of using parallel streams in Java 8?

Answer 7

Concurrent execution on multiple threads

Question 8

Which package contains the Predicate functional interface in Java 8?

Answer 8

java.util.function

Question 9

What is the purpose of the forEach method in the Stream API in Java 8?

Answer 9

To apply a function to each element of a stream