Java Interface Interview Questions and Answers
Here we are going to cover all the top most interview questions on interface in java one by one. This article is very important for any java interview point of view.
Now start here in detail java interface questions and answers.
abstract class
(1) What is interface in java?
Java interface is a blueprint of a class and it is used to achieve fully abstraction and it is a collection of abstract methods.
(2) Can we achieve multiple inheritance by using interface?
Yes, we can achieve multiple inheritance through the interface in java but it is not possible through class because java doesn't support multiple inheritance through class.
(3) How to declare an interface, write a syntax?
The syntax of declaring the interface in java by using interface keyword :
interface FirstInterface
{
fields;
methods;
}
(4) Can we create an object of an interface?
No, we cannot create an object of interface.
(5) Can we declare the interface as final?
No, we can't declare the interface as final because the implementation of the interface is provided by another class. If we make the interface as final, it will throw a compile-time error.
(6) Which keyword java compiler add before interface fields and methods?
In an interface, Java compiler adds public, static and final keywords before fields or data members and add public abstract keywords before methods. In other words, all the fields are public, static and final and all the methods are public and abstract by default in an interface.
(7) Does interface extend Object class by default?
No, Interface does not extend Object class in java by default but all the classes extend Object class by default.
(8) Can an interface extend another interface?
Yes, an interface can extend another interface.
(9) Can an interface extend a class?
No, A class can implement an interface but interface cannot extend a class.
(10) Can we put a static method in interfaces?
No, we cannot put static methods in interfaces because all the methods are by default public and abstract in the interface and we cannot use abstract and static keywords together.
(11) Can we declare an interface with the abstract keyword?
Yes, we can declare abstract keyword with interfaces but there is no need to write abstract keyword with interfaces because all the interfaces are abstract by default.
(12) What is default keyword in an interface?
By the help of default keyword, we can keep non-abstract method in java interface i.e with method body{}. This is the new feature of JAVA 8.
Syntax of default keyword :
interface Test
{
default void show()
{
-----
-----
}
}
Syntax of default keyword :
interface Test
{
default void show()
{
-----
-----
}
}
(13) What is marker or tagged interface?
Marker interface is an interface that has no data member and method like Serializable, Cloneable, etc.
(14) Can we declare a constructor in the interface?
No.
(15) After compilation of interface program, .class file will be generated for every interface in java... true or false.?
This is true.
(16) Can we change the value of a field in interface after initialization?
No, Because all the fields of the interface are by default final.
(17) Difference between abstract class and interface?
There are many differences between abstract class and interface.
abstract class
- Through abstract class, you cannot achieve multiple inheritance.
- You can keep non-abstract method(with method body) in the abstract class.
- In the abstract class, fields are not public, static, final and methods are not public abstract by default.
interface
- Through the interface, you can achieve multiple inheritance.
- In an interface, you can't keep non-abstract method but since java 8 it is possible.
- In an interface, fields are public, static, and final and methods are public and abstract by default.
Read More :
Java Collection Interview Questions.
Java Comparable Interface with Example.
Java Comparator Interface with Example.
Java Encapsulation with Example.
Java Comparable Interface with Example.
Java Comparator Interface with Example.
Java Encapsulation with Example.
Above we saw some most important Interview questions and answers on java interface which is mostly asked in core java interviews.
Good Job, it's more useful
ReplyDeletethanks :) :)
Core Java Important Questions Part 1
DeleteGreat Article android based projects
DeleteJava Training in Chennai
Project Center in Chennai
Java Training in Chennai
projects for cse
The Angular Training covers a wide range of topics including Components, Angular Directives, Angular Services, Pipes, security fundamentals, Routing, and Angular programmability. The new Angular TRaining will lay the foundation you need to specialise in Single Page Application developer. Angular Training
Learned a lot of new things from your post!Good creation ,It's amazing blog
ReplyDeleteCore Java Online Training
Java Online Course
Java Online Training Bangalore
The list of your blogs are very helpful for those who want to learn programming.Thanks for your post.
ReplyDeleteJava training in chennai
Great stuff and useful for job seekers!
ReplyDeleteitcodehub
Nice site....Please refer this site also Our vision success!Training are focused on perfect improvement of technical skills for Freshers and working professional. Our Training classes are sure to help the trainee with COMPLETE PRACTICAL TRAINING and Real time methodologies
ReplyDeleteDot Net Course in Chennai | Best Dot Net Training Institute in Chennai
Testing Courses in Chennai | Best Software Testing Training Institute in Chennai With Placement
Java Training in Chennai | Core Java Training in Chennai | java course and certification
PHP training in chennai | Best PHP Training in chennai
Interface can contain static methods from java8
ReplyDeleteyes
DeleteAll the interview questions are so helpful. Thank you for providing this detailed post. It is very helpful to me.
ReplyDeletegreat article about java interface interview questions and answers.
ReplyDeletethanks
Please update it. Interface can contain static methods. If you are declaring a static method in the interfaces and do not provide a body, it will give a compilation error . Something like "Method require a body instead of semicolon"
ReplyDeleteThis blog is so cool. I am learning Java Training online. This blogs helps me find out better understanding about salesforce training. Thank you for this blog!
ReplyDeleteThank you for sharing this amazing post. Looking forward to reading more.
ReplyDeleteVisit us: Java Training
Visit us: Java Course
thank you for sharing this article. VISIT:Python Online Training
ReplyDeletethank for sharing. Visit:Online IT Training
ReplyDeleteExcellent information provided by you through this post. I follow all the mentioned information.If you are looking for Interview Questions and answers website then you can visit Just Crack Interview, here you will find interview questions and answers for developer, software engineer, bankers etc.
ReplyDeleteI read this post your post so nice and very informative post thanks for sharing this post
ReplyDeletehttps://www.acesoftech.com/
I’m following your blog from last few days and there are amazing post.
ReplyDeletehttps://www.acesoftech.com/
Hey Nice article
ReplyDeleteBook publishing in India
Hey Nice article
Book Publisher in india Hey Nice article
self publishing in India
Hey Nice article
Delhi Book Fair
Hey Nice article
odisha book fair 2022
Hey Nice article
kolkata Book Fair
Hey Nice article
jaipur literature book fair 2022
"JAVA95" seems to be a term that combines the programming language Java with the number 95. While it is unclear what specific context "JAVA95" refers to, best cameras for video, Java is a widely used programming language known for its versatility and robustness. It is utilized in various domains, including web development, mobile app development, and enterprise software solutions. The number 95 may represent a version number, a specific Java library, or a reference to the year 1995 when Java was first released. Regardless of the exact meaning, Java remains a popular and relevant programming language in the software development industry. It offers a vast ecosystem of libraries, frameworks, and tools, making it a preferred choice for many developers. If there are specific questions or discussions related to "JAVA95," a blog commenting website can serve as an excellent platform to engage in conversations, best mirrorless camera, share knowledge, and exchange experiences about Java programming. Let's explore the exciting world of Java and leverage the power of this language to create innovative and robust applications.
ReplyDelete"JAVA95" seems to be a term that combines the programming language Java with the number 95. While it is unclear what specific context "JAVA95" refers to, Java is a widely used programming language known for its versatility and robustness. It is utilized in various domains, including web development, Best cameras for streaming, mobile app development, and enterprise software solutions. The number 95 may represent a version number, a specific Java library, or a reference to the year 1995 when Java was first released.
ReplyDeleteGreat blog, This blog is very informative. You can java course from an institute. You can search java training course in Kanpur, Mumbai, Delhi and other cities in India.
ReplyDeleteThanks for sharing this java interview question. This question really help students. Students can learn Java course from any Institute which provide Java Training Institute in Kanpur.
ReplyDeleteThis is one of the great blog. very nice and creative information.iam really impressive your topic.Thanks for sharing.
ReplyDeletelearn python course in Chandigarh
This blog is truly commendable! It emphasizes the importance of searching for the best Java training course to enhance your understanding of the subject, ultimately leading to a successful career Building a Strong Foundation in Java Programming
ReplyDeleteThank you for sharing this! I always appreciate coming across such exceptional content brimming with valuable insights. The ideas put forth are outstanding and quite intriguing, making the post not only informative but also highly engaging. Your dedication to producing such fantastic work is truly commendable. Keep up the excellent work.
ReplyDeletevisit: Data Visualization Techniques for Effective Analysis
Thank you for sharing this! I always appreciate coming across such exceptional content brimming with valuable insights. The ideas put forth are outstanding and quite intriguing, making the post not only informative but also highly engaging. Your dedication to producing such fantastic work is truly commendable. Keep up the excellent work.
ReplyDeleteYour blog help me a lot for doing my college project on Java Programming. With a focus on practicality, aspiring Unlocking the Power of Data Science will discover a myriad of career options and abundant learning resources available to embark on this exciting journey.
ReplyDelete