HTML

Is it Possible to Create Object or Instance of an Abstract class in Java?

Hello guys, how are you doing? Hope you are doing well. It's been long since  I shared a core Java interview question in this blog, so let's start with that. Earlier I have shared one of the frequently asked questions in Java, can we make an abstract class final in Java and my readers really liked and asked for more such questions. So, today I am going to talk about whether you can create an instance of an Abstract class in Java or not? This is another interesting core Java question that you will find on telephonic interviews, a written test that has multiple-choice questions and most notably Oracle certified Java programmer certification like OCAJP 8  and OCAJP 11.

Top 5 Books to Improve Coding and Programming Skills - Must Read, Best of Lot

Learning a Programming language, like Java, Python, or C++ is easy, but learning to write good code is not. Writing good code is more Art than Science and also an important differentiating factor between an average programmer vs. a good programmer. Since most of the programmers often look for inspiration and resources to improve their coding skill, I decided to share some of the good books which can help them to improve their coding.  Since many universities, colleges, and training courses only teach programming languages but not the art of coding, it still remains one of the self-learned skills which many programmers acquired either in Job or working in real-world projects.

Top 5 Spring Cloud Annotations Every Java Developers should Learn

If you are developing Java application for Cloud then you should learn Spring Cloud, a great framework and extension of popular Spring framework which can help you to develop a cloud-native Java application. Spring Cloud provides several necessary services required for a cloud-based Java application like configuration management, service discovery, circuit breakers, intelligent routing, micro-proxy, a control bus, one-time tokens, global locks, leadership election, distributed sessions, cluster state etc. On top of that, it builds on the Spring framework so it automatically provides the essential features like dependency injection and inversion of control, which results in loosely coupled and easy to test Java application.

Top 5 Courses to Learn Spring Boot in Depth in 2019 - Best of Lot

Hello guys, if you remember, one of my goals was to learn Spring Boot in 2019, and I have started working towards it. As I have talked about my 3 point action plan to learn new technology, the first step is to attend some online courses and start building from that. If you are not sure what is Spring Boot and why should you learn Spring Boot, then let me tell you that it should be the first Java frameworks you should learn in 2019. The Spring Boot makes it really easy to work with the Spring framework by removing all the starting hurdles with respect to setup and configuration. In one word, it makes it possible to write a Spring-based Java application and run them like core Java applications, like from the main method.

How to read a CSV file with Header in Java using Jackson library - Example Tutorial

Hello guys, today I am going to show you how to read a CSV file in Java with a simple example of Jackson API. For a long time, I only knew that Jackson can be used to parse JSON but later realized that you can also use it to parse or read CSV file in Java. The Jackson DataFormat CSV library allows you to read a CSV file in just a couple of line and its really powerful and feature rich. For example, you can read a CSV file with a header or without a header. You can even read a tab-delimited text file like CSV. It's also highly configurable and allows you to define columns separator to read a text file with any delimiter. You can even use it to directly convert the CSV data into Java objects, just like we do while reading JSON String in Java.

Top 10 Java 8 Tutorials, Classes, and Courses - Best of Lot, Must Read

It's a long time since Java 8 was released, and there are so many Java 8 tutorials are written by Oracle, bloggers, and other peoples, but which should you read? Which tutorials are worth of your time? Actually, this question is asked to me by one of my reader called John, he was asking me about some good Java 8 tutorials, which he can read to start with. This encouraged me to take a look at some of the Java 8 tutorials available on the internet and form a list of best. I have just used three criteria, content, language, and length. Because tutorials complement books, they should not be like the book. They should be small enough to complete in a few hours and complete enough to give useful information. I also like tutorials, which discusses practical problems and examples.

10 Frameworks and Libraries Software Developer can Learn in 2020 - Best of Lot

Hello Guys, we are just a few months away from 2020 now, and many of you might have already made your goals about what to learn in 2020, but if you haven't then you have come to the right place. In this article, I am sharing some of the best framework and libraries for web development, mobile app development, and big data, an application developer can learn in 2020. The New Year will be all about the mobile. Machine learning, and next-generation web with a greater focus on big data technologies like Hadoop and Spark, but you can still learn the popular Java and Web development frameworks like React, Node.js, Spring Boot to take your career to the next level. These frameworks are tried and tested and will be here for at least the next 5 years to come.

Top 5 Books to learn SQL and Database design in 2019 - Best of Lot

The SQL (Structured Query Language) is one of the most essential skills of a programmer. I would rate this skill similar to UNIX if you are a professional programmer because it doesn't matter whether you are Java, C++, or a .NET developer, you are bound to write SQL queries. Since a database is an integral part of any modern Java or Web application, the Interviewer always preferred  candidates with excellent SQL skills. Now, the big question comes, how a programmer can learn SQL? Does just knowing how to query a table is enough? If you remember, insert, update, delete, and select, then are you a competent SQL programmer? What about indexes, query plans, triggers, views, stored procedures, and other advanced SQL concepts? What about writing complex queries involving joins, subqueries, derived tables, etc.? Well, all those are very important to be a competent full stack developer.

Spring HelloWorld Example in Java using Annotation and Autowiring

Spring framework has gone a couple of releases since I last share the Spring hello world example with XML configuration. In this article, I am going to explain to you how to create a Spring hello world example with Spring 4.2 release and by using Annotation for dependency injection and autowiring. So no more XML files to specify bean dependencies. It's a simple program that shows how you can use the Spring framework to create Services that are loosely coupled. The example will show you the basic concept of dependency injection by creating a simple Java application that greets the user. It's actually a little bit complex version of a simple Helloworld program but if you need decoupling and in-direction you need to accept some level of complexity. That's the price you need to pay to achieve the flexibility in your code.

Top 5 Free BlockChain Online Courses for Programmers to Learn in 2019

Hello guys, how are you doing? hope you all are having a great time and working towards your goal this year. I have been sharing a lot of courses and tutorials in this blog about what to learn in 2019, starting from tools to frameworks, from libraries to programming languages, but one of the most important technology, you can learn in 2019 is the Blockchain technology. It's one of most talked about technology at the moment and considered to be the next big thing after the invention of the internet as they provide a way to attain digital trust on the Internet.

10 Essential JVM Options for a Java Production System

Hello guys, this is a brief guide of relevant JVM options which you will often see in production Java systems. As a Java developer, you should know what these JVM options means, their importance, and how they affect your application. You will find that most of the JVM options are related to heap memory, garbage collection and to log some details, e.g., heap dump, necessary for troubleshooting heap related issues like a memory leak or excessive memory consumption. It's Ok if you don't know these Java virtual machine options yet, but you should be familiar with them, and that's the objective of this article. Btw, how do you find the JVM options your application is using? Well, you can see the startup scripts through which your application is started.

Top 7 Free courses to learn Selenium Driver in 2019 - Best of Lot

Testing is an integral part of software development and we have long been relied on manual testing by testers and QA professional to ship quality software and find bugs, but that's not sustainable anymore. There is an increased focus on automation testing nowadays and Selenium is leading the way with its web drivers. If you don't know what is selenium, it's a free automation testing tool for web applications. It can work with different web browsers like Chrome, Firefox, Internet Explorer, Opera and simulate human-like behavior. By using Selenium you can programmatically interact with all the different elements on a webpage. You can click on them, input text, extract text and so much more.

Learn Tree Data Structure in 5 Minutes - Binary Tree (BT), Binary Search Tree (BST), and Balanced Tree (AVL vs Red Black)

The Tree data structure is one of the essential data structures, but unfortunately, many programmers don't pay enough attention to learning Trees, particularly advanced tree data structures like balanced trees like AVL and Red-Black tree. Many of them think that knowing just array and the linked list is enough for programming interviews, but when they face questions about a tree, like the difference between binary tree and binary search tree, or difference between binary search tree and a self-balanced tree-like AVL tree or Red-Black tree, they become speechless.

Top 5 Free courses to learn Android for Beginners in 2019

Hello guys, Happy New Year 2019. I am sure you all have made your goals and started planning on how to achieve them. If you are passionate about creating mobile games and applications and want to learn how to develop Android apps or want to become an Android application developer then you have come to the right place. In this course, I am going to share some of the best and free Android development courses for Java programmers and others. You might know that earlier Java was the only language which is used to create Android applications but since last year, Google has announced Kotlin as the official language for Android app development which means you can use either Kotlin or Java to create Android apps.

Top 10 JavaScript (Frontend + Backend) Frameworks for Web Developers

There is no doubt that JavaScript is now the #1 programming language in the world and also the king of web development. If you want to become a web developer who can quickly create websites like you see on the internet then a good knowledge of JavaScript and various, popular JavaScript web development framework is very important for you. These framework has completely changed the way people develop web application a decade ago. After node.js, its even possible to create a complete web application from front-to-back using just one programming language, JavaScript. That's why it has become the favorite programming language of all Full-stack Web Developers.

Top 5 Free Python Courses for Beginners to Learn Online - Best of Lot

Hello guys, If you are a beginner looking for some Free Python resources to start your programming journey then you have come to the right place. Earlier, I have shared a couple of free Python Programming books and some of the best courses to learn Python which was not free. Some of my readers asked me to share some free online courses to learn Python and it made sense. I personally like starting from free resource and today I'll share a couple of good Python programming courses which are absolutely FREE. You can take these online courses to learn Python at your own pace, at your own time, and at your place. This is a great advantage of online learning, the flexibility it provides is just awesome. 

The Right way to Remove Objects while Iterating over ArrayList in Java - Example Tutorial

One of the common problems many Java Programmers face is to remove elements while iterating over ArrayList in Java because the intuitive solution doesn't work, e.g., you just cannot go through an ArrayList using a for loop and remove an element depending upon some condition. Even though java.util.ArrayList provides the remove() methods, e.g. remove (int index) and remove (Object element), you cannot use them to remove items while iterating over ArrayList in Java because they will throw ConcurrentModificationException if called during iteration. The right way to remove objects from ArrayList while iterating over it is by using the Iterator's remove() method.

Array Data Structure in Java - 10 Examples

Along with the String, the array is the most used data structure in Java. In fact, String is also backed by a character array in Java and other programming languages. It's very important for a Java programmer to have good knowledge of array and how to do common things with array e.g. initialization, searching, sorting, printing array in a meaningful way, comparing array, converting an array to String or ArrayList and doing some advanced slicing and dicing operation with an array in Java. Like my previous tutorials 10 examples of HashMap in Java, I'll show you some practical example of array in Java. If you think, any important operation is not included, you can suggest their examples and I'll add them to this list.

Top 5 Object Oriented Analysis and Design Interview Questions for Programmers, Software Engineers

Testing the design skill of a candidate is quite common in programming job interviews. Questions like, how do you design a vending machine or a traffic control system is very popular in object-oriented programming language interviews, like Java and C++. Designing a software System requires good experience and knowledge of tools of object-oriented design and analysis. You should not only be good at OOP fundamentals like Abstraction, Inheritance, Polymorphism, Encapsulation, Coupling, Cohesion, Association, Aggregation, or Composition but also on several crucial object-oriented design principles like SOLID Principles of Object-Oriented Design, which is building block for writing flexible and maintainable code.

Top 5 Free Courses to Learn React in 2019 - Must Join, Best of Lot

React JS or React is one of the most popular frameworks or Javascript library for building user interfaces. It's backed by Facebook, and it's often viewed as an alternative to the tremendous Angular framework by Google. React is also very flexible, fast, easy to learn and fun to work with. It is designed to make the process of building modular, reusable user interface components simple and intuitive and that's why most of the modern GUI and web applications are build using React framework. It is developed at Facebook and it focuses on the 'View' aspect of MVC in web applications. The component-based development is one of the biggest advantages of the React library which is both rich and extensible.

Top 10 SQL and UNIX Interview Questions for Programmers

The SQL and UNIX are two of the most essential skills for any programmer. It doesn't matter whether you are applying for the job as Java developer or C++ developer, Python developer or Ruby programmer, SQL and UNIX always have some role to play in your career. It's even essential for people who have less to do with programming like application support guys, business analysts, project managers, and subject matter experts.  Hence, it's imperative for any programmer or IT professional to prepare both SQL and UNIX well before going for any job interview. This becomes even more important if you are going for a support engineer role instead of for a development role because than the importance of SQL, Database, and Linux skill increases as compared to the programming language you know.

Top 5 Free Courses to learn TypeScript in 2019 - Best of Lot

If you are interested in learning TypeScript or Angular, one of the popular JavaScript framework for developing front-end, which uses TypeScript and looking for some resources e.g. books, tutorials and courses then you have come to the right place. In this article, I am going to share some of the best, free TypeScript online courses you can use to learn this powerful programming language. For those who don't know TypeScript, it's a new dynamically typed programming language from Microsoft which augments JavaScript's programming syntax by adding some new features which help in object-oriented application development, particularly introduction of Types.

Top 25 Java Date, Time, and Calendar Interview Questions Answers

The Date and Time API is a very important one for day to day Java development work but many interviewers don't ask enough questions on this topic. Most of the questions are based on either Java Collection framework like  HashMap, ConcurrentHashMap, or ArrayList or on multi-threading concepts like volatile, synchronized and atomic variables. This is not good and I think many interviewers have realized that a good understanding of date and time API is also important for a good Java developer. That's the main reason for an increasing number of date, time and calendar based Java interview questions in recent time, particularly in last a couple of years.

Top 5 Free Servlet, JSP, and JDBC Online Courses for Advanced Java Developers - Best of Lot

If you are a Java developer working on a Java JEE projects like a Java Web application running on Tomcat or Glassfish, or you want to get into that by learning server-side technologies like Servlet, JSP, and JDBC then you have come to the right place. In this article, I will share some free online courses to learn Servlet, JSP, and JDBC at your own pace. If you want to become a rockstar Java web developer then you must have a good understanding of these basic web technologies before you learn frameworks like Spring and Hibernate. These frameworks work on top of these basic technologies and if you don't know them then you would often struggle to debug and troubleshoot problems in the real world.

What is difference between Heap and Stack Memory in Java JVM

One of the many traits of a good programmer is how well he understands the fundamental and if you want to check the fundamentals of Java programmer than asking the difference between heap and stack memory is a good choice. Even though both are part of JVM and both consumers memory allocated to the Java process, there are many differences between them e.g. Heap memory is shared by all threads of Java application but Stack memory is local to each thread. Objects are created in heap memory but method frames are stored in Stack memory, and size of heap space is much bigger than the small size of Stack in Java. Even if you know this much information about heap and stack in Java, you are one of the better candidates, but let's see some more details to impress the interviewer.

Top 5 Design Patterns Books for Java Developers - Best of Lot

Design patterns are an essential topic for object-oriented programmers, e.g. Java and C++ developers. It becomes even more important as your experience grows because everybody starts expecting a lot more from you in terms of writing quality code. I often receive emails from intermediate and senior Java developers about progressing to the next level, like how to become Tech Lead, Team Lead, or a software architect; knowledge of design patterns play an important role in taking more technical responsibility. While the GoF book is the bible for object-oriented design patterns, in my opinion, it is a bit too dry and academic.

Top 5 Free Courses to learn Machine Learning and Deep Learning in 2019

Hello guys, Happy New year 2019. We are already in the second week of January and I am sure you all have made your goals and may be looking for the ways and resources to achieve them. If one of your goals is to learn Machine learning and Deep learning in 2019 then you have come to the right place. In this course, I am going to share some of the best free courses to learn Machine learning and Deep learning online. Btw, If you are thinking to learn Data Science, Machine learning, or Deep learning than you are not alone, more and more people are starting with these advanced skills around the world.

Difference between the getRequestDispatcher and getNamedDispatcher in ServletContext?

The ServletContext class provides two methods getRequestDispatcher(String url-pattern) and getNamedDispatcher(String name), which can be used to dispatch a request to a particular servlet. The main difference between getRequestDispatcher() and getNamedDispatcher() method is that former accepts a URL pattern or path while later agrees with a Servlet name defined in deployment descriptor or web.xml file, both return an instance of RequestDispatcher class, which can further use to forward or redirect a request in Java web application. Let' see some more detail about these two methods and how they work.

Top 5 Free JavaScript Online Training Courses for Web Developers - Best of Lot

Hello guys, If you want to learn JavaScript by yourself and looking for some free resources like books, sites, and tutorials then you have come to the right place. In this article, I am going to share some of the best free JavaScript online courses you can join to learn JavaScript by yourself, on your own schedule and at your own place. A lot of people are learning JavaScript and the number is only increasing by each passing day, and why not? It's the #1 web development language. It got tons of useful frameworks and libraries like Angular, ReactNode.js, and jQuery which makes web development really easy.

12 Advanced Java programming books for Experienced developers - Part 2

This is the second part of 12 must-read advance Java programming books for intermediate and experienced Java programmers. In the first part, I have shared books to learn and master concurrency, performance, design patterns, and Java collection framework, which is essential for every Java developer irrespective of experience. On the other hand, In this article, I will talk about more advanced concepts, like security, Java 8, best practices, etc., which is more important for senior Java developers. As an experienced Java developer, a lot is expected of you. Junior developers look at you for guidance, and project managers look at you to solve problems and bail them out at critical junctures.

Top 10 C++ Interview Questions and Answers from Investment Banks

Today, for a change I am not sharing any Java interview question, but I am sharing a few C++ interview questions. There is a good demand for developers who know both Java and C++, particularly in investment banking domain, as a lot of high-performance application like client connectivity, exchange connectivity, and order management systems (OMS) are written in C++. If you know both Java and C++ then you have a great chance to get a job in big investment banks like Barclays, Nomura, Deutsche Bank, and other Wall Street Firms.

Top 5 Free JavaScript Books for Beginners - Download PDF or Read Online

The internet is full of good things, and one of them is free eBooks and PDF. Programmers can almost run anything by these free books. Earlier I have shared some of the free JavaScript tutorials, and in this article, I am going to share 5 good books to learn JavaScript, which is open to read online or allow you to download PDF for offline reading. JavaScript is probably another language I recommend someone who knows Java, Why? Because it's really ubiquitous. There is almost no website that is not using JavaScript in one or another format. Some use JavaScript for client-side scripting and animation, while others use JavaScript on the server-side with libraries like Nodejs and Reactjs it forms the unique triangle with HTML and CSS.

Top 10 Free Courses to Learn Algorithms and Data Structure in 2019 - Best of Lot

Algorithms and Data Structure are two of the most fundamentals and important topics from Computer Science which is used everywhere in software development. I strongly believe that a good knowledge of these two topics are also key to become a better programmer because a person who has a good understanding of algorithms and data structures can make thoughtful choices and write programs which can handle changes better and perform well. They are also important to crack coding interviews at top tech companies like Google, Microsoft, Amazon, Facebook, and Apple, which puts a lot of emphasis on candidate's ability to use existing data structure and algorithms to solve complex problems they have never seen before.

Top 5 books to learn Java Virtual Machine, Garbage Collection, and Performance in-depth

In the last couple of years, I have seen a trend of many Java developers wants to learn more and more about JVM internals and how Java Virtual Machine and it's different component works. This trend was not so strong in the last decade, but with more and more focus on concurrency, performance, and scalability, Java developer is exploring JVM internals, Garbage collection, and Performance tuning in more detail. Unfortunately, there are not many good books to learn about JVM internals and its different components but fortunately, we have an excellent Java Virtual Machine specification to learn fundamentals. It is also the most up-to-date reference because Java and JVM are kept changing, especially after Java 10.

How to Reverse an Array in place - Java Coding Problems with Solution

It's relatively easy to reverse an array if you have the luxury to use another array, but how would you reverse an array if a temporary buffer is not allowed? This is one of the testing array interview questions, which often proved tricky for Java and other beginner Programmers. But, don't worry, I'll tell you how you can solve this problem without losing your cool. Well, you can also reverse an array in place without using an additional buffer. If you know how to access array elements and how to loop over an array in Java using traditional for loop, you can easily solve this problem without using additional space or in-place as described in many Algorithms books and courses, and on Coding interviews.

Top 5 Free Courses to learn Nodejs in 2019 - Best of lot

Node JS has completely changed the way JavaScript is used for development. Earlier JavaScript was considered as a client-side language because it runs on a browser and mostly used for client-side validations, animations, and interaction. Node.js takes that to the next level by allowing JavaScript to run on a server-side, which means you can now write JavaScript applications which can execute without a browser. Node JS uses Google Chrome's execution engine and asynchronous processing to do this. All you need to is include node.js script in your application, and you are ready to create server-side applications in JavaScript, which wasn't possible until a few years back.

5 Free SQL Books For Beginners and Experienced - Download PDF or Read Online

There is no doubt that SQL is one of the most essential skills for Programmers, IT professionals, Software Engineers, Quality Analysts, Project Manager, Data Scientist, Database admins, and Business Analysts. I had even mentioned this as one of the top skills in my post about 10 things every programmer should know, if you haven't read that yet, you can read it here, it's completely worth of yours time. Since many Enterprise applications use the relational database at their backend, like Oracle, Microsoft SQL Server, MySQL, it's crucial to learn SQL to work with those applications and use the data stored on those databases.

Top 5 Amazon Web Services or AWS Courses to Learn Online - FREE and Best of Lot

Hello guys, if you are thinking about cloud, cloud-computing and looking at the various cloud providers like AWS, GCP, or Azure then you are going in the right direction. Future lies with Cloud and it's very important for every developer to learn about cloud computing solutions. When we talk about Cloud the first thing comes in mind is AWS, the biggest Cloud Computing platform and that's why I suggest a lot of developers learn it. If you want to learn Amazon Web Services, popularly known as AWS and looking for some awesome resources like books, courses, and tutorials then you have come to the right place. In this article, I am going to share some of the best Amazon Web Services or AWS online courses which will help you to learn this revolutionary and valuable technology free of cost.

Top 10 Free Python Programming Books - Download PDF or Read Online

Every Programmer loves free eBook and free courses, even more, if it comes from renowned technical book publishers like Oreilly and Manning. In the last article, I have shared some of the best free Java programming books, and today I am going to share some of the equally best free Python Programming books. These books are not illegal copies that are uploaded into the internet, but they are the legal books, made free by their authors and publishers, much like free Udemy courses, which their instructor made free for educational and promotional reasons. Though these are not full-fledged books but concise eBooks, they are very informative and comprehensive enough to learn things like Data Science and Functional programming in Python.

How to make a new array in Java?

There are several ways to create an array in Java, for example, you can declare the array without initializing it, or you can create and initialize the array in the same line. If you want to make an array with values, then you need to first decide which type of array you want to create? e.g., do you want String array, which can contain String objects like "abc," "def," or do you want to create an int array which contains int values like 10, 20, etc. In Java, you can create an array of any type, including both primitives like byte, int, long and objects like String, Integer, and other user-defined objects. Let's some code to make a new array in Java.

Top 5 Free Courses to Learn Swift Programming in 2019

Hello guys, how are you doing this lazy Saturday? You might be thinking, as a Java developer why I am suggesting you learn Swift, but the truth is that I am not suggesting you abandon Java and join Swift, I am suggesting you join Swift if you want to develop iOS applications. We all use Apple's product and we love them, I have used iPod, iPhone, iPad, Apple Watch, and even MacBook and every time I use their product I just say wow and Swift are no different from that. It's a programming language from Apple so you will find all the features which make Apple product great. It's simply because Apple has kept education in mind while creating it. If you have an iPad, you might have also seen the Swift Playground app, which is also a great app to learn Swift and iOS.