java 8 interview questions

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Java 8 Interview Questions

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In this article we will be going through java 8 interview questions in details.

So stick to the article and get the most out of this article.

It has been years of support and contribution of java to the world of computing, software development domain.

Not only theory on java skills, but also practical and real projects are much needed to get the actual skills.

In this article we present you some of the Top java interview questions that are mainly asked by the companies that help to test your skills and knowledge at peak. Java 8 has got many new features .

Top Java 8 Interview Questions for freshers.

 

1 .What are the new specifications updated in java 8?

Ans – The new features that are listed on Java 8 are as follows: 

● Lambda Expression 

● Method References 

● Optional classes 

● Functional Interface

● Default method 

● Nashon

● Stream API

● Date API

2 .What is meant by Functional interfaces?

Ans- It is known because it has a single abstract (unimplemented ) method. It provides target types for lambda expression and method references.

The annotation for creating a new functional interface is “@FunctionalInterface”.

3.Explain optional class. 

Ans- optional class is contained that may or may not contain non null value. The final class is present under the java.util package. 

 

4 .What are the default methods?

Ans In this method users can access the body of the interface. It contains default keywords , the use of the default methods is “Backward Compatibility”. Thus, adding this method will simply break the collection framework implementations.

SYNTAX 

public interface vehicle{

default void result(){
system.out.resultln(“I am a Boy”);

}
}

5. What are the main specifications of Lambda expressions? 

Ans- The specifications are as follows:

● It enables to treat functionality as a method argument or code as data.

● A function can be made without any class.

● Multiple Parameters can be closed in parenthesis with separation of commas.

● The body of lambda expressions can contain zero, one or more statements.

● If there is only one statement curly braces it is not mandatory.

6. What is the SAM interface?

Ans- SAM interface is a functional interface having only one abstract method . They provide the target types for lambda expression and method references.

7. What is the stream API ? Need of Stream API.

Ans- It is the new feature of Java8 that provides a special class for processing objects from a source such as collection .

We need the Stream API because 

● It supports aggregate operation which makes processing easy and user friendly. 

● It allows Functional Style Programming.

● It supports the features of parallel operations.

8. What is the need for a limit method in Java8 ? 

Ans- The limit method specifies the limit of the elements. The size specified in limit(C) , it prints the stream of size of ‘C’.

SYNTAX:

limit(C)

where c is the size of an element . 

9. How can we create a functional interface?

Ans-

@ FunctionalInterface // annotation for functional interface

interface FuncInterface {


public int multiply(int a, int b);

}

public class Java8 {

  

public static void main(String args[]) {

    

FuncInterface Total = (x,y) -> x*y;

     // simple operation of multiplication of 'x’ and 'y’

       

System.out.println("Result: "+Total.multiply(30, 60));

    }

}

10. Write a code to print 5 random numbers using for Each in Java 8 platform?

Ans – 

import java.util.Random;
class Java8 {
 public static void main(String[] args) {

  Random random = new Random();
 
random.ints().limit(5).forEach(System.out::println);
 }
}

11. Explain MetaSpace in Java 8 ?

Ans- It is the storage of the class. The area where are the all the classes are stored is called meta space.

Till Java7 permgen was the storage class . After the introduction of java8 PermGen was replaced by MetaSpace .

It is dynamic as it grow dynamically and it does not have any size limitations.

12. What are the chrono units of Java 8?

Ans – ChronoUnits is used to replace the integer values that are used in the old API for representing the month, day and time etc.

13. Write a code in Java8 program to arrange and then convert a sorted array into stream. 

Ans – Parallel sort is used in this question to sort an array of integers.

import java.util.Arrays;

public class Java8 {

 public static void main(String[] args) {
  int ar[] = {100, 56, 200,49, 14, 391 };
 
Arrays.parallelSort(ar);
  // Sorted the Array using parallelSort()
  
 
Arrays.stream(arr).forEach(n -> System.out.print(n + " "));
  /* Converted it into Stream and then
    
printed using forEach */ }
}

Conclusion:

In this post we have understood the latest features of java 8. We have covered some of the top interview questions and answers . I hope you will get benefits through this post in challenging the interview processes of java positions and deal with the programming aspect of Java8.

If any of the doubts and queries left behind please comment in the comment section, we will get to you ASAP.


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