Learn Java and Programming through articles, code examples, and tutorials for developers of all levels.
Top 50 Database and SQL Interview Questions Answers for Programmers
Top 21 Web Development Interview Questions with Answers in 2023
3 Examples of Anonymous Class to Learn Lambda Expression better in Java 8
Hello guys, you may be thinking why I am talking about Anonymous class now when many Java programmers have already switched to Java 8 and many have already moved on from Anonymous class to Lambda expression in? Well, I am doing it because I am seeing many Java programmers who find it difficult to write and read code using lambda expression in new Java 8 way. It's also my own experience that if you know the problem first, you can better understand the solution (lambda expression). Some of you might remember, the opening scene of MI 2 (Mission Impossible 2), when Nekhorovich says to Dimitri that "Every search for a hero must begin with something that every hero requires, a villain. Therefore, in our search for a hero, Belairiform, we created the monster, Chimera".
Top 27 Spring Security Interview Questions Answers for Java Developers
Top 20 Jenkins and CI/CD Interview Questions Answers for Java Developers
Hello guys, if you are preparing for Java developer interview or DevOps Interview, one tool which you should know well is Jenkins, the king of Continuous Integration and Continuous build, and one of the most desirable skill companies look on experienced programmers now a days. Earlier, I have shared best free Jenkins courses for programmers to learn this useful tool as well as Interview questions on DevOps, Docker, and Kubernetes and in this article, I am going to share 20 frequently sked Jenkins and CI/CD Interview questions with answers for both beginners and experienced developers.
Top 20 Agile and Scrum Interview Questions and Answers for PM, Programmers and Testers
3 Examples of flatMap() of Stream in Java
Hello guys, if you are doing Java development then you must have come across the flatMap() method on Stream and Optional Class. The flatMap() method is extension of map() function as it does both flattening and mapping (or transformation) instead of just transformation done by map() method. I have explained the difference between map() and flatMap() earlier in detail, but just to revise, let's revisit it. If you have a list of String e.g. {"credit", "debit", "master", "visa"} then you can use the map() method to get a list of integer where each value is length of corresponding String e.g. list.stream().map(s -> s.length()) will produce {6, 5, 6, 4}. This is called transformation because you have transformed an stream of String to a Stream of integer.
Top 50 Advanced Java Garbage Collection and Performance Interview Questions and Answers
Top 40 Perl Interview Questions and Answers for Programmers
[Solved] How to check if two String are Anagram in Java? Example
How to create a String or int Array in Java? Example Tutorial
10 Examples of an Array in Java
How to find 2nd, 3rd or kth element from end in linked list in Java? Example [Solved]
Difference between array and Hashtable or HashMap in Java
A couple of days back someone asked me about the difference between an array and a hashtable, though this is a generic data structure and programming question, I'll answer it from both a general programming perspective as well on Java perspective where Hashtable is not just a data structure but also a class from Java Collection API. Even though both array and hashtable data structure are intended for fast search i.e. constant time search operation also known as O(1) search, the fundamental difference between them is that array require an index while hash table requires a key which could be another object.
How to use Map.compute(), computeIfPresent() and ComputeIfAbsent in Java? HashMap and ConcurrentHashMap Example
What is Blocking Deque in Java? How and When to use BlockingDeque? Example Tutorial
How to use LinkedList in Java? Singly LinkedList and Doubly LinkedList Example Tutorial
Hello friends, we meet again on our journey to Java. I hope you guys are enjoying Java and are trying hands-on too. Today we are gonna discuss a very easy topic (yeah, I mean it :p). But, do not get carried away just by "easy", this is the hottest topic asked in various interviews, exams, and development purposes too. So, what's the wait? Let's start! As usual, let's start with a scenario. Let's say you want a data structure that stores data in a sequential manner, like an array. But, you don't know the size yet while initializing the data structure. Arrays don't support that, they need a size beforehand. So, what should we do? Do not worry, as Java is here to help us again. Let's explore it then!
How to get First and Last Element of LinkedList in Java [Example]
What is HashSet in Java? How and When to use Set Data Structure? Example Tutorial
Hello guys, we meet again for our journey of learning Java. Today, we are gonna learn something very fruitful and easy. Hope you all are excited and ready. I would recommend you guys to go through the HashMap or TreeMap article which goes over hashing as this topic has some of its features. So, What's the wait? Let's start! Suppose you guys are given the task of storing car names (yes, I love cars :p). Now, how would you store it? If you guys have some questions, here are the requirements. The car names may increase over time. So, logically, an array is not what we are looking for.
Top 20 TypeScript Interview Questions and Answers for Web Developers
Top 51 JavaScript Interview Questions for 1 to 2 Years Experienced Developers
Top 20 AWS Interview Questions Answers for Developers and DevOps Engineers
How to Prepare for AWS certified Security Specialty Exam in 2023
Hello guys, if you are preparing for AWS Certified Security Specialty exam in 2023 then you have come to the right place. Earlier, I have shared best AWS Security specialist courses and my thoughts and courses on cracking AWS Solution architect exam and today, I will share how you can prepare for AWS Security certification in depth. The AWS Certified Security Specialty" certification is one of the most esteemed credentials in the industry. There is now an official designation for data analysts on their resumes and applications. Two of today's most hotly debated topics, cloud computing, and security, come together with the AWS Security Specialty certification. If you're in the security field, bringing your skills to the cloud is a natural next step in your career development.
Why Every Developer should learn Cloud Computing (AWS, AZURE or GCP) in 2023
Hello guys, if you are wondering whether you should learn Cloud Computing in 2023 then my only advice to you is just learn it. It doesn't matter whether you are a Developer or DevOps, sooner or later you will have to learn Cloud, there is no escape here and learning now is your best option. Now most of the job description for Java developers list that they will prefer candidates with familiarity and experience working in cloud platforms like AWS or Azure and if you don't have them then you will be left behind. Nowadays, whenever I open LinkedIn, I see people on my network getting AWS certified or Azure Certified or Google Certified and its not a coincidence, they are doing because their job need Cloud skills and their companies are also encouraging them to learn Cloud and become a certified Cloud Developers and that's the main reason I suggest every programmer and developer to learn about Cloud computing.
How to use Deque Data Structure in Java? Example Tutorial
How to use Recursion in JavaScript? Example Tutorial
How to get the first and last item in an array in Java? Example Tutorial
Java FileReader + BufferedReader Example
10 Examples of print(), println() and prinf() methods In Java - PrintStream
Hello guys, if you are working in Java or just started with Java then you have must come across statements like System.out.println("Hello world") to print something on console or command prompt. This is actually the first statement I wrote in Java when I started programming and at that time I didn't realize how it work and what is System and PrintStream class and what is out here but now I know and I am going to explain all this to you in this article, along with PrintStream class and its various print methods like print(), println() and particularly printf() to print various objects in Java. But, Before we get to the 10 examples of Printstream printf() in Java, let me tell you a little bit more about what exactly Printstream is.
Top 20 Project Management Interview Questions and Answers
Top 20 Cloud Computing Interview Questions and Answers
Hello guys, if you are preparing for Java developer interview or DevOps Engineer Interview, or a System admin, , knowledge of Cloud Computing is mandatory nowadays. It's even more important if you are interviewing for Cloud Engineer. Earlier, I have shared best Cloud Computing Courses and Books and today, I am going to share 20 Cloud Computing Questions for interviews. You can use these questions to revise essential Cloud Computing Concepts before interviews. If you are new to Cloud Computing space then these questions are also good to learn more about Cloud Computing by doing research.
Top 20 Cyber Security Interview Questions and Answers
Top 20 Artificial Intelligence Interview Questions and Answers
Top 20 Bootstrap Interview Questions Answers for Web Designers and Developers
Hello guys, if you are preparing for web design and development interview and looking for Bootstrap interview questions then you have come to the right place. Bootstrap is one of the most popular CSS Framework and almost all websites uses Bootstrap for their classy look and feel and bigger buttons and form elements. Earlier, I have shared HTML 5 Interview Questions and best online courses to learn HTML, CSS and Bootstrap courses and today, I am going to share bootstrap interview questions with answers. Here is a chance for you to make sure that you go into that Bootstrap interview with your head up high. Being ready for that interview is the major step that you can make as you seek to impress the interview panel on the interview day.
Chain of Responsibility Pattern in Java? Example Tutorial
Top 20 Ansible Interview Questions Answers for DevOps and Senior Developers
Top 20 YAML Interview Questions Answer for Developers and DevOps Engineers
Top 20 UI and UX Design Interview Questions and Answers
Top 20 Unity Interview Questions and Answers for Game Developers
Top 20 Unreal Engine Interview Question and Answers for Game Developers
Top 20 Mathematics and Statistics Interview Questions and Answers
Top 21 Chef Interview Questions and Answers for DevOps Engineers
Top 20 Shell Scripting Interview Questions and Answers
Have you struggle with Shell Scripting interview questions before? Have you been having problems in finding out the kind of questions asked in a Shell Scripting interview? If you have experienced this then it is high time that you find a solution. You cannot lose that dream job anymore and yet you can find with ease all you require to pass your interview. If that interview is a few days away, worry no more because you will get before that panel fully prepared and ready for the day by going through these common shell scripting questions.
Difference between Spring vs SpringBoot Framework in Java
Difference between Proxy and Decorator Pattern in Java
Top 20 Docker Interview Questions Answers Java Developers and DevOps
Top 30 Gradle Interview Questions Answers for Experienced Java Developers
Top 24 Node.js Interview Questions with Answers for 1 to 2 Years Experienced Web Developers
Top 30 Spring Core, Spring MVC and Spring Security Interview Questions Answers
[Solved] How to find the Longest common prefix in Array of String in Java? Example Tutorial
How to check if a node exists in a binary tree or not in Java? Example Tutorial
How to find Kth Smallest Element in a Binary Search Tree? [Solved]
How to find the maximum sum level in binary tree in Java? Example Tutorial
Difference between Thread.yield and Thread.sleep in Java? Answer
Top 10 Projects You can Build to Learn Spring Boot in 2023
10 Tools Every Software Engineer Should Learn In 2023
Hello guys, as a software engineer, staying up-to-date with the latest tools and technologies is essential to your success and one way to keep yourself up-to-date is to learn new framework, libraries and tools. Earlier, I have shared 5 Java Frameworks to learn in 2023 and in this article, we will introduce you to 10 tools that every software engineer should learn in 2023. The list includes, both essential and advanced tools from Git and Docker to TypeScript and GraphQL, which you will need in your day to day development, particularly on web development.
10 examples of crontab commands in Linux
When to use PUT or POST in a RESTful API and Web Service? Answer
[Solved] java.lang.ClassNotFoundException: org.Springframework.Web.Context.ContextLoaderListener in Java and Spring
Context.ContextLoaderListener in your Spring-based Java Web application.
Cause: This error comes when you are using the Spring MVC framework in your Java Web application and configured org.springframework.web.context.ContextLoaderListener as a listener in your deployment descriptor also known as web.xml, but the JAR which contains this class is not available in the web application's CLASSPATH.
How to fix org.springframework.beans.factory.BeanCreationException: Error creating bean with name X [Java Spring]
BeanInstantiationException: Could not instantiate bean class [X]: No default constructor found; nested exception is java.lang.NoSuchMethodException: X.()
Here X is the class, which is declared as Spring bean. The error clearly says that the default constructor is not present in class X.
Difference between Serializable vs Externalizable in Java - Interview Question
Top 10 Git Commands Every Programmer Should Learn in 2023 (with ChatGPT Examples)
Hello guys, Git is one of the most important skill for programmers, developers and data scientist and if you don't know git then you will struggle working in a team. If you want to learn Git in 2023 then you can start with these essential Git commands. I have explained the command and give you example. For examples, I have asked ChatGPT to see how it explains and I was amazed to see the response so I have included here for my own reference. I don't if ChatGPT will remain free forever but I am taking screenshot for the questions which I am asking so that I can keep a record for myself and you in future as ChatGPT is the best instructor I have got today and its helping me to learn and revise several key concepts.
What is the use of DispatcherServlet in Spring MVC? Interview Question Example
Top 15 Spring Data JPA Interview Questions with Answers
26 Spring Framework Interview Questions Answers for 2 to 4 years experienced Java Developers
What is @Bean Annotation in Spring Framework? Example Tutorial
Top 53 Java Programs for Coding and Programming Interviews
How to Find/Print Leaf nodes in a Binary Tree in Java without Recursion - Example
What is WeakHashMap in Java? HashMap vs WeakHashMap Example Tutorial
Hello friends, we are here today again on our journey to Java. I hope everyone is fine and ready to board our train of knowledge. Today we are gonna learn something very interesting and very exciting. Today's topic will definitely be very useful in coding and programming. This topic would surely decrease your time complexity, and space requirements for any task very significantly :p So what's the wait? Let's start!
How to delete multiple elements from a LinkedList in Java? SubList() Example
What is TreeMap in Java? HashMap vs TreeMap Example Tutorial
8 Examples of Primitive Data Types In Java (int, long, boolean, float, double, byte, char, and short)
Hello guys, Data types are first few things you should learn when you start learning a programming language and when it comes to learn Java, there are 8 primitive data types which you should know. These are divided into three categories, numeric, text, and boolean values. Numeric data types can be further divided into two like natural numbers and floating pointing numbers. But, Before we get to a list of the 10 examples of primitive data types in Java, let me tell you a little bit more about what the primitive data types are. There are essentially 8 primitive data types in Java. They are int, byte, short, long, float, double, boolean, and char. The primitive data types are not considered objects and represent raw values. These primitive data types are also stored directly on the stack.
What is Normalization in SQL? 1NF, 2nd NF, 3rd NF and BCNF Example Tutorial
10 points on TCP/IP Protocol, Java Programmers should Know
How ThreadLocal variables works in Java? Explained
Top 10 Java NIO Interview Questions Answers for 5 to 10 Years Experienced Programmers
Top 20 Access Modifier Interview Questions Answers for 2 to 3 Years Experienced Java Developers
Access modifiers is one of the essential concept in Java and every programmer should be familiar with, and because of its importance, its also a popular topic in Java interviews. Access modifier can be applied to class, method, fields, and variables and as the name suggests they control the access. Like who can access that particular class, method or variable. For example, public modifier provides universal access which means any public class, method or variable is accessible by everyone and everywhere. In other words, you can access a public class both within the package and outside the package.
How to use @JsonCreator and @JsonPropertOrder Jackson JN Annotation in Java? Examples
How to convert List Of of Object to Map of Object (key, value) In Java? Example Tutorial
Difference between JIT and JVM in Java? Answered
Top 10 Programming Languages to Learn in 2023 [UPDATED]
How to write to a File with try-with-resource in Java? Example Tutorial
Top 30 Advanced Java Interview Questions for Experienced Developers
Hello guys, I have shared a lot of questions from Java Interviews in this article, so much so that many of my reader search Javarevisited for any Java interview question they come across. While In the past, I have shared Java concurrency questions, Java collections questions, Java questions on design patterns, and many tricky Java questions but a lot of people asked me to share more practical questions for experienced Java developers. Means, more advanced Java questions for 5 to 7 and even 10 years of experienced Java developers.
How to Enable Disable Spring Security in Spring Boot? Example Tutorial
How to Find Lowest Common Ancestor of a Binary Tree in Java? Example Tutorial
Hello guys, if you are wondering how to find the lowest common ancestor of a binary tree in Java then you are at the right place. Earlier, I have shared 40+ binary tree questions and today I am going to share solution of one of the popular binary tree question here. To find the lowest common ancestor of a binary tree in java requires that we run through a binary search tree and how it operates. What then is a binary search tree? A Binary tree is a data structure in which each node can have at most two children. That is, each node in the binary tree will have data, left child and right child. The first node of the tree is called the Root.
React Native vs Flutter? Which is better to learn for App Development in 2023?
Angular vs React vs Vue.js ? Which is better to learn web development in 2023?
Top 11 JavaScript Frameworks and Libraries to Learn in 2023 - Best of Lot
10 Reasons to learn Node.js for Web Developers in 2023
Top 10 Google Cloud Certifications You can Aim in 2023 - Best of Lot
How Long Does It Take To Learn Data Science in 2023?
Hello guys, if you want to become a Data Scientist in 2023 but wondering how long it take to learn all the Data Science skills required to become to a Data Scientist then you are at the right place. Earlier, I have shared best Data Science courses and Data Science Interview Questions for Job Interviews and in this article, I will talk about the time it take to become a Data Scientist in 2023. Data science is a simple term, is preparing the data for analysis starting by cleaning, aggregating, and manipulating data for this action using scientific methods, statistics, machine learning algorithms to extract insights from this data and power business decisions.