Top 5 Tools for Testing REST APIs and RESTful Web Services in 2023 - Best of Lot

Hello guys, If you are a Java or web developer working on REST APIs and RESTful web services and looking for some tools to test your APIs and web services then you have come to the right place. Earlier, I have shared the best books and courses for RESTful web services and in this article, I am going to share five awesome but easily accessible and free tools to test your REST APIs. These REST API testing tools will help you to test your APIs as you build, starting from unit testing to integration testing and then fully automating your resting to create a regression pack. You can also use these tools to interact with your REST API during the development phase for quick tests. 

What is the use of DispatcherServlet in Spring MVC Framework?

If you have worked with Spring MVC then you should know what is a DispatcherServlet? It's actually the heart of Spring MVC, precisely the C of MVC design pattern or Controller. Every single web request which is supposed to be processed by Spring MVC goes through DispatcherServlet. In general, its an implementation of Front Controller Pattern which provides a single point of entry in your application. It handles all incoming requests. It is also the bridge between Java and Spring. Btw, the DispatcherServlet is like any other Servlet is declared in the web.xml with a URL pattern but the only special thing is that the URL pattern for dispatcher servlet is enough to map every single web request to DispathcherServlert.

7 Reasons to use Spring Framework for Creating RESTful Webservices in Java

REST has now become a standard way to develop web services and when it comes to Java, there are many frameworks and libraries available like JAX-RS, Restlet, Jersey, RESTEasy, Apache CFX, etc, but I encourage Java developers to use Spring framework to develop RESTful web services. But, some of you might ask, why use Spring Framework to develop RESTful web services in Java? What is the advantage and why it's better than other frameworks and libraries available out there? Well, the most important reason I think to use Spring for developing RESTful web service is that you can use your Spring MVC experience to develop RESTful web services.

Spring Hello World Example in Java using Dependency Injection

Hello All, In this Spring framework tutorial, you will learn how to write the hello world example in the Spring framework. This should be your first tutorial to start learning the Spring framework, as it gets the ball rolling. While coding and running this example, you learn a lot about the Spring framework, Spring XSD files, necessary JAR files, and more importantly how the Spring framework works. This HelloWorld program in Spring framework is an extension of the classical Java hello world program, which you might have seen earlier. This program is written using the Dependency Injection design pattern by using the Spring Frameworks' IOC container.  Even though now you can configure Spring dependency using annotations and Java configuration, this example uses a traditional XML way to configure dependencies.

Eclipse - How to Fix java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet in Tomcat

Problem: You are getting java.lang.ClassNotFoundException exception complaining that Spring's DispatcherServlet class is not available in the classpath. This error is coming while running a Spring MVC based Java application from Eclipse and Tomcat as Server (running inside Eclipse IDE itself). You have either included spring framework JAR files manually by yourself or you are using Maven to download and manage dependent JAR files. Here is the stack trace of this error :

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1523)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:525)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:507)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:126)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1043)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4957

20 Essential Tools for DevOps Engineers and Senior Developers in 2023

Hello guys, If you are thinking to become a DevOps Engineer in 2023 or just want to take your DevOps skills to next level then here is a list of some of the essential tools for DevOps professionals. DevOps engineers and senior developers are responsible for managing and automating the software development process, from planning and coding to testing and deployment. To accomplish these tasks efficiently and effectively, they require a range of tools and technologies that can help them streamline their workflows and increase productivity. In this article, you will learn about 20 essential tools that every DevOps engineer and senior developer should have in their toolkit. 

What is bean scope in Spring Framework? Singleton, Prototype, Request scopes Example Tutorial

Java classes or POJO which are managed by Spring Framework are called Bean or Spring Bean and Bean scope in Spring framework or Spring MVC is scope for a bean managed by Spring IOC container. You may know that Spring is a framework that is based on Dependency Injection and Inversion of Control and provides bean management facilities to Java application. In Spring-managed environment bean (Java Classes) are created and wired by the Spring framework. Spring allows you to define how those beans will be created and the scope of the bean is one of those details. Scope are similar to access modifiers in Java which specifies visibility of a particular class. 

How View Resolver works in Spring MVC? [InternalResourceViewResolver Example]

Hello guys, if you are wondering what is view resolver in Spring MVC and what role InternalViewResolver class plays in Spring MVC then you have come to the right place. Earlier, I have explained to you how Spring MVC works internally and how it processes HTTP requests coming to your web application. One of the important parts of that processing was resolving views, which is handled by the ViewResolver interface, which is the V part of MVC. They are responsible for returning correct views to the client, both in the Spring MVC application as well as on REST APIs. In this article, you'll learn more about view resolvers in Spring MVC by explaining the InternalResourceViewResolver class. 

Difference between @RestController and @Controller Annotation in Spring MVC and REST

The @RestController annotation in Spring MVC is nothing but a combination of @Controller and @ResponseBody annotation. It was added into Spring 4.0 to make the development of RESTful Web Services in Spring framework easier. If you are familiar with the REST web services you know that the fundamental difference between a web application and a REST API is that the response from a web application is generally view (HTML + CSS + JavaScript)  because they are intended for human viewers while REST API just returns data in form of JSON or XML because most of the REST clients are programs. This difference is also obvious in the @Controller and @RestController annotation.

Top 5 Java Frameworks for Microservices Architecture in 2023 - Best of Lot

Hello Java Programmers, if you are thinking about Microservice Architecture and Cloud-Native development in Java and exploring options like frameworks, libraries, and technologies then you have come to the right place. Earlier, I have shared the best Microservice courses, and Microservice design patterns and in this article,  I am going to share the best Microservice Framework for Java developers. While you may know that Spring Boot and Spring Cloud is the leading framework for developing Microservice applications in Java, there are a couple of more options as well like MicroNaut, DropWizard, and Quarkus IO. In this article, you will learn about the top 5 frameworks you can use to develop Microservice in Java.

How to validate HTTP POST Request Payload on Spring MVC controller? Example Tutorial

Hello guys, if you are wondering how to validate incoming request payload in Spring MVC based Java web application then you have come to the right place. You can use JSR-303 Bean Validation Framework and @Valid annotation in Spring MVC to check the request data on POST request.  Earlier, I have shared best Spring MVC courses for Java developers and In this tutorial, we are going to discuss how to validate incoming payloads on the Spring MVC controller which is also can be defined as validating the request body in the RESTful web services. So first let's have a look at validating the request body in the RESTful web services. Think you have a JSON post request and you are going to consume it. There should be a validation to this post request as the requested input will be zero or in a not accepted format.

Top 20 Spring Framework Testing Interview Questions Answers for 2 to 5 Years Experienced

Testing is an important part of Software development but many people don't pay attention to it only to find bugs in the later stages of development that can be easily avoided by unit testing. When it comes to Java and Spring Boot development, we are lucky to have JUnit, Mockito, JsonPath, AssertJ, and some in-built testing facilities on Spring Framework and Spring Boot for our testing needs. Since the advent of DevOps, there is an increased focus on automation testing and that's why unit testing and integration testing has become important topics on Java Interviews and it's essential for Java developers to have in-depth knowledge about how to test a Spring framework and Spring Boot based Java application.

Spring Data JPA @Query Example - Tutorial

Hello guys, if you are learning Spring Data JPA framework or using Spring Data JPA in your project and are not sure how to use @Query annotation then you have come to the right place. Earlier, I have shared the best Spring Data JPA courses and Spring Data JPA Interview questions and in this article, I am going to show you how to use @Query annotation from Spring Data JPA to create dynamic SQL queries. Spring is a popular Java application framework for creating enterprise applications and Spring Boot is an evolution of the Spring framework which helps to create standalone applications in a minimal effort. 

Spring Boot + Hibernate Tutorial and Example for Java Developers

Hello guys, if you want to learn how to use Spring Boot and Hibernate together in a Java application and look for examples and tutorials then you have come to the right place. In the past, I have shared how to use Spring Boot with MyBatis and Spring Boot + Redis example and In this article on Spring Boot, we will discuss how to integrate Spring Boot with Hibernate. We will build a simple Spring Boot application and use Hibernate to store the data. So first, let's look at what is Hibernate in Java? Hibernate framework provides an abstraction layer which means programmers need not worry about implementation. Hibernate will implement different modules for developers internally like writing queries to perform CRUD operations on the database and establishing connections to different kinds of databases. This is a Java-based solution for object-relational mapping.

What is @SpringBootTest Annotation in Java and Spring? How to use it? Example Tutorial

Hello guys, if you want to learn what is @SpringBootTest annotation and how to use this annotation to test your Spring Boot application then you have come to the right place. The @SpringBootTest annotation is a powerful annotation in Spring framework which is used to load entire application context for Spring Boot application and create integration test. It allows you to test your application in the same way as it runs on production. You can use this annotation to test your controller, service, repository classes and every other part of your Java Spring Boot application. Earlier, I have shared the best Spring Boot courses and Spring Boot Testing interview questions and in this article, I am going to explain to you about @SpringBootTest annotation. Before diving into how to use @SpringBootTest annotation. It is good to briefly introduce Testing in Spring boot. 

Difference between @ContextConfiguration and @SpringApplicationConfiguration in Spring Boot Testing?

Hello folks, what is the difference between @ContextConfiguration and @SpringApplicationConfiguration is one of the frequently asked Spring Boot Testing interview questions which is often used to check if the candidate knows about how to unit test Spring boot application. Even though both @ContextConfiguration and @SpringApplicationConfiguration annotations are used along with SpringJUnit4ClassRunner to specify how to load the Spring application context, there is a subtle difference between them. Although @ContextConfiguration does a great job in loading application context it doesn't take full advantage of Spring Boot features. Spring Boot applications are ultimately loaded by either SpringApplication ( in the case of the JAR) or SpringBootServletInitializer. 

What is @SpringBootApplication Annotation in Java and Spring Boot? Example Tutorial

Hello guys, if you are wondering what is @SpringBootApplicaiton annotation and how to use it then you have come to the right place. Today, we'll learn about the @SpringBootApplication annotation, one of the most important annotations from the popular Spring Boot framework, which has changed the way Java developers use the Spring framework for writing Java applications. In this article, I'll explain to you the meaning of @SpringBootApplication and its use in a simple Spring Boot application. We use @SpringBootApplication annotation on our Application or Main class to enable a host of features e.g. Java-based Spring configuration, component scanning, and in particular for enabling Spring Boot's auto-configuration feature.

Difference between Spring Boot and Spring Cloud Framework

Hello guys, if you are doing Java development and created Microservices then you may know that Spring Boot and Spring Cloud are two popular Java-based frameworks that are widely used for building enterprise-level applications, particularly Server side backend Java application. Both of these frameworks are developed by the Spring team and offer unique features that make them stand out in the market. While both are used for building scalable, high-performance, and robust Java applications, they serve different purposes and are used in different ways. The aim of this article is to help developers understand the differences between Spring Boot and Spring Cloud and make an informed decision on which framework to use for their next project.

Difference between BeanFactory and ApplicationContext in Spring Framework

The difference between BeanFactory and ApplicationContext in Spring framework is another frequently asked Spring interview question mostly asked Java programmers with 2 to 4 years experience in Java and Spring. Both BeanFactory and ApplicationContext provide a way to get a bean from the Spring IOC container by calling getBean("bean name"), but there is some difference in their working and features provided by them. One difference between the bean factory and application context is that the former only instantiates bean when you call getBean() method while ApplicationContext instantiates Singleton bean when the container is started,  It doesn't wait for the getBean to be called. 

What is a Spring Data Repository? JpaRepository, CrudRepository, and PagingAndSortingRepository Example

Hello Java developers, if you are wondering what is Spring Data Repository interfaces like JpaRepository, CrudRepository, and PagingAndSortingRepository and how to use them then you have come to the right place. Earlier, I have shared the best Spring Data JPA courses and in this article, I will give you an overview of different Spring Data Repository interfaces and how to use them with step-by-step examples. The Java Persistence API (JPA) is the standard way of persisting java objects into relational databases. 

How to return different HTTP status code from a Spring MVC controller? Example Tutorial

Hello guys, if you are wondering how to return different HTTP Status codes from a Spring MVC controller then you have come to the right place. You can use @ResponseCode annotation on Spring MVC to send different HTTP codes to the client as part of the HTTP response. If you are developing REST APIs then you can even @RestControler to do that job. This article will demonstrate how to return different HTTP statuses for a Spring MVC controller. Prior to implementation, all we need to understand what is with the HTTP return types and why we need them. Let's have a quick look into this.

How to create a Java Web application using Spring MVC Framework? Example Tutorial

Hello guys, if you are looking for an example to create a Spring MVC application then you have come to the right place. Earlier, I have shared the best courses to learn Spring MVC, Books, and interview questions and In this tutorial, we are going to explain how to create your first MVC application with the spring framework. At present, there are many applications in the world, and developing them is also varies according to the performance, type of the application, and many other factors. However, one of the primary languages used for application development is java with the model-view-controller (MVC). Here comes the spring framework for application development and will go through an example project to explain this further.

How to transpose a Matrix in Java? Example Tutorial

Hello guys, if you are wondering how to transpose a matrix in Java then you have come to the right place. Matrix related coding problems are great way to learn multi-dimensional array and nested loop and they are good programming exercise for beginners. In the past, I have taught you how to multiply matrices in Java and how to add/subtract matrices in Java, and in this article, I will show you how to create transpose of a given matrix in Java, but before that let's first understand what is transpose of a matrix means and how do you transpose a matrix in maths? Well, a transpose of a matrix is nothing but a matrix whose rows and columns are reversed. 

[Solved] How to find and Print Armstrong number between 0 and 9999 in Java? Example

An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 153 is an Armstrong number, since 1**3 + 5**3 + 3**3 = 153, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371. Along with usual beginner exercises like calculating factorial, reversing a string, or calculating prime numbers, this is a good exercise to build programming logic. It teaches you basic programming techniques of how to use the operator for something which is not obvious.

Java Program to Multiply Two Matrices - Matrix Multiplication Example

How to write a Java program to multiply two matrices in Java is a very good programming exercise to get familiar with the two-dimensional array in Java. this example teaches about how to multiply arrays, how to access elements from a multi-dimensional array, how to pass them to a function etc. Since the matrix is a natural representation of a multi-dimensional array in Java, they are often used to illustrate real word matrix exercises e.g. the calculating sum of two matrices or calculating the difference of two matrices, etc. It's also one of the popular Matrix based coding problems you can find on coding interviews. 

Why use @Override annotation in Java? Coding Best Practice Example

@Override annotation was added in JDK 1.5 and it is used to instruct the compiler that method annotated with @Override is an overridden method from super class or interface. Though it may look trivial @Override is particularly useful while overriding methods that accept Object as a parameter just like equals, compareTo or compare() method of Comparator interface. @Override is one of the three built-in annotations provided by Java 1.5, the other two are @SuppressWarnings and @Deprecated. 

Top 10 Hiring Tips for Technical Interviewers and Hiring Managers

Hello guys, For a change, this article is not for candidates who are preparing for interviews, but for those programmers who are responsible for taking interviews. At some point in your career as a programmer, you will have the responsibility to hire developers for your company. This is a big responsibility and your ability to select the right candidate will directly affect your company's future. This is more visible in small companies than the larger organization where a pool of interviewers exists. In a start-up, if you are a technical lead and responsible for hiring, it's a tough job. You have to hire the right candidate which fits in companies culture and competent enough to do the job they were hired for. To be frank, conducting interviews is as hard as giving interviews.

10 Reasons to Learn Java Programming Language in 2023 and Why Java is Best

Java is one of the best programming languages created ever, and I am not saying this because I am a passionate Java developer, but Java has proved it in the last 20 years. Two decades is a big time for any Programming language, and Java has gained strength every passing day. Though there are times when Java development slows down, Java has responded well. Earlier with groundbreaking changes in the form of Enum, Generics, and Autoboxing in Java 5, performance improvement with Java 6, functional programming using the lambda expressions in Java 8, and Google's choice of language for Android apps development keeps Java as a front-line programming language.

How to use MyBatis in Spring Boot application in Java? Example Tutorial

Hello guys, In this tutorial, we will discuss how to create a spring boot project with MyBatis. First, you need to have a better understanding of what is MyBatis and its use-cases. MyBatis is a SQL mapping framework with support for custom SQL, stored procedures, and advanced mapping. Although Spring Boot does not officially support MyBatis, the MyBatis community has created a Spring Boot startup for MyBatis.This is the most commonly used open-source framework for implementing SQL databases access in java applications.

Top 42 Programming Interview Questions with Answers for 1 to 3 Years Experienced

For the last few years, phone interviews also known as the telephonic round is the single most popular way to screen candidates in a programming job interview. It's easy for both parties to gauge each other, the candidate doesn't need to travel to the prospective Employer's premises and the Interviewer also doesn't need to make any necessary arrangements. This is the second part of my article on programming interview questions, in the first part, I got feedback that it is a little bit heavy on coding-based questions and many programmers asked me to share a similar list for the telephonic round of programming Interviews. In order to clear the telephonic round and proceed to the next round, you must be good enough to answer all the questions related to your Job description.

Top 16 JMS (Java Messaging Service) Interview Questions and Answers

Java messaging Service or JMS interview questions is one of the important parts of any Core Java or J2EE interview as messaging is a key aspect of enterprise Java development. JMS is a popular open-source Messaging API and various vendors like Apache ActiveMQ, Websphere MQ, Sonic MQ provides an implementation of Java messaging API or JMS. Any Java messaging services or JMS interview can be divided into two parts where the first part focuses on fundamentals of JMS API and messaging concept like What is topic, What is Queue, publish-subscribe or point to point model, etc, While the second part is related to JMS experience with particular JMS provider.

Top 20 Questions Candidate Should Ask in Programming Job Interviews?

From the first round to HR round, from telephonic to face-to-face, in almost all kind of programming interviews, there will be a time when Interviewer will give you a chance to ask questions. Many programmers are too concern about asking questions, and they politely decline ; Well it's your chance to learn about the Job you are going to do, and you shouldn't let this opportunity goes away. The interviewer, also judges you by your questions; a good, thoughtful, positive question can create the great impression on Interviewer's mind. It also shows that  the interest of a candidate for a Job.

Top 20 Algorithms Interview Questions for Programmers and Software Engineers

Hello All, If you are preparing for Programming job interviews or looking for a new job then you know that it's not an easy process. You got to be lucky to get a call from recruiter or hiring manager and make to the first round of interview at any stage of your career but it is even more difficult at the beginner level when you are searching for your first job. That's why you can't just take your chance lightly. You got to be prepared to grab that chance and for that, you must know what is expected from you on the interview. What is asked, what topics should you prepare, etc? I have blogged a lot about what you can find helpful articles in this blog but to recap let me tell you that apart from data structure questions, System Design Questions, and Programming language-specific questions like Java or Scala, most of the programming job interviews also ask algorithm based questions.

10 Free Courses to Learn System Design and Software Design in 2023 - Best of Lot

Hello guys, if you are preparing for System Design Interview or just want to improve your Software design skills and looking for best free resources like tutorials and free online courses then you have come to the right place. In the past, I have shared best System design courses, books, websites, and popular System design questions but a lot of you asked for free resources and that's why I am going to share best free System design courses I found online. These online System Design training courses are completely free and provides a diverse knowledge about different System design concepts and process. They are also created by experienced trainers and teacher who has gone through the same process and available on trusted online platforms like Udemy and YouTube. You can join one or more of these free System design courses to not only improve your Software design skill but also to prepare for your next System Design Interview. 

How Spring Security works internally? DelegatingFilterProxy and springSecurityFilterChain Explained

Spring Security is a very straight-forward framework. It protects your application by locking URLs. It provides both authentication and authorization facility for Java web application, but the big question is how does it do that? How exactly Spring Security works internally? I have seen this Spring Security question coming up several times on recent Spring interviews, so I thought to summarize what I know about working of Spring Security. The most important thing to remember is that Spring security works by using servlet filters. Since, an HTTP request is first passed to a matching filter before passing it to servlet, you can use a filter intercept an HTTP request and that's what Spring security does it. 

System Design Interview Prep Guide 2023 - Topics, Questions, and Resources

Hello guys, if you are preparing for Software Engineer or Software developer interview then you may know that how difficult it is to prepare for System Design given its open ended nature and vastness but at the same time you cannot ignore it. In Software Engineering world, if you are applying for a Senior Engineer / Lead / Architect / or a more senior role, System Design is the most sought-after skill, and hence one of the most important rounds in the whole process. If you mess this up, nothing else would matter. If you get it right though, you’re looking at a raise of at least tens of thousands of dollars annually. So how do you ace your system design round? Well, here’s what I did while preparing for my interviews with Facebook, Google, and Amazon, and it worked out rather well. I did end up creating a checklist for myself which got me through most of my rounds, so if you follow a similar path you should be able to come up with something that works for you as well.

Top 20 HTML Interview Questions with Answers for 1 to 3 Years Experienced

Hello guys, if you are preparing for web developer interview then you must prepare for HTML questions. HTML, CSS, and JavaScript is the backbone of web development and that's why every web develop is supposed to have good  knowledge of these three technologies. In the past, I have shared JavaScript Interview Questions and CSS Interview questions and today, I will share 20 HTML Interview Questions with answers for web developer interview. If you have done web development work then most likely you already know answers of these question but if you feel lacking then you can always go through these best HTML online courses to learn and revise concept in depth. 

How to enable disable Form elements in web page using jQuery? Example Tutorial

In last couple of tutorials you have learned how to get all selected checkbox and radio buttons, and in this tutorial, you will learn how to enable/disable form elements using jQuery. A form element e.g. a text field, radio buttons and checkbox, all represented using input tag can be enabled or disabled by adding an attribute called "disabled". It's similar to "checked" attribute we have seen for checkbox and radio buttons. If this attribute is not present then element is enable, but if this attribute is present then you can use disabled=true to disable the form element and disabled=false to enable the form elements as shown in our example.  Like previous example of checking/unchecking checkbox, you can use prop() jQuery function to enable/disable form element if you are running on jQuery 1.6 or higher version and attr() function if you are running on jQuery 1.5 or lower version. 

React.js useState, useEffect and useDispatch Hooks Example - Tutorial

Hello guys, if you want to learn about Hooks in React.js like useState, useSelector, useEffect, and useDispatch then you have come to the right place. In the past, I have shared the best React courses, websites, and books and in this article, I am going to show you what is React hooks and how they make coding and statement management easier in React.js. If you remember, React.js is created by Facebook and ever since it came out in 2013 and since then, it has become one of the biggest players in the front-end development community. Today, React.js demand for frontend development is more than any other framework or library. There are several reasons for its popularity. React is flexible, easy to learn, programmer-friendly, and most importantly, it's high performing. 

How to check if Checkbox is checked in JQuery? Example Tutorial

Hello guys if you are wondering how to check if a checkbox is checked using jQuery then you have come to the right place. Earlier, I have shared, how to check/uncheck checkbox or how to find all unchecked checkboxes using jQuery and in this article, I will share how to check if a particular checkbox is checked or not. While working in Java web application front end, written using JSP, HTML, CSS, and JavaScript, we often need to check status of checkbox e.g. whether a particular checkbox is checked or not? One example of this is checking is checking, whether user has accepted terms and conditions before submitting form. Thankfully, JQuery provides a nice and easy way to find status of checkbox. 

How to reload/refresh a page using JavaScript and jQuery? Example

Hello guys, if you are wondering how to reload or refresh a web page then don't worry JavaScript provides several ways to reload or refresh an HTML page but the standard way to do this job is by using window.location object. This object provides a reload() method which instructs the browser to reload the page. The browser can do it from its cache or from the server, which depends upon optional parameter i.e. reload(true) will reload the page from the server but reload(false) will only reload the page from the browser's cache, which may or may not represent the current version at the server.

Top 10 System Design Courses for Software Engineer Interviews in 2023 - Best of Lot

Hello guys, if you are preparing for System design interview and looking for best online courses to learn essential System design concepts like load balancing, scalability, architecture as well as how to solve popular System design questions like how to design YouTube, WhatsApp, Parking Lot, Library System as well when to use NoSQL and SQL then you have come to the right place.  In the past, I have shared best System Design Books, Free System design courses,  System design prep guide, and System Interview Questions and in this article, I am going to share best places to learn System design in 2022. Before we get to the best  Before we get to the 9 best courses that will teach you everything you need to know about system design interviews, let me tell you a little bit about what it really is.

Top 5 Online Courses to Learn Kubernetes in 2023 - Best of Lot

Hello guys, Kubernetes has become a very popular tool and skill today in the container management community, and it's one of the most in-demand skills and a must-learn tool for both DevOps engineers and Developers. It is a tool written in Golang and it is created by Google. There are many things you need to take care of when working in production environments with microservice patterns and containers. These include version control, health check, rollback mechanism, and scaling. Kubernetes provides the management and orchestration capabilities to deploy containers in accordance with all the necessary mentioned things.

Top 10 Scala and Groovy Frameworks Java Developers can learn in 2023 - Best of Lot

Hello guys, Groovy and Scala have been around for some time. Some useful Groovy and Scala frameworks can help Java developers create better applications and products like Microservices et al. l. If you are interested in learning the best Scala and Groovy framework, then you have come to the right place. In the past, I have shared the best courses to learn Scala and Groovy, and In this article, we are going to take a look at some of the best Scala and Groovy frameworks that can be useful in Java development  Akka, Lagom, Play, Spock, Gradle, and Grails. I'll also share links to some valuable courses to learn these practical Groovy frameworks.

How to redirect a page or URL using JavaScript and JQuery - Example

Redirecting a web page means, taking the user to a new location. Many websites uses redirects for many different reasons, e.g. Some websites redirect users from the old domain to new domain, some redirect from one page to another e.g. a more relevant page. If you are a Java programmer and worked previously with Servlet and JSP, then you might be familiar with SendRedirect and Forward methods, which are used to redirect users in web applications. Actually, there are two kinds of redirect, Server side redirect, and client-side redirect. In Server side redirect, the server initiates redirection, while in a client-side redirect, the client code does the redirection. Redirecting a web page using JavaScript and JQuery is a client-side redirection.

Top 10 Udemy Courses for Python, JavaScript and Web Development in 2023 - Best of Lot

Hello guys, Udemy, one of the most popular online learning platforms, is known for its sale where you can buy a $200 course for just $10, and they are running a sale now. It's actually an excellent time to buy some quality courses as you won't get another chance to buy the course at a price as low as $9.9, but the big question is which courses you should buy on Udemy in 2023? I always purchase courses from the reputed instructor and teach evergreen and in-demand skills like Java, Python, Microservices, Docker, Kubernetes, and AWS. I generally buy a lot of courses in Udemy sales and then access them whenever I need them. Though, I must warn you Udemy is addictive, and I often buy more classes than I need, so beware of that and buy courses you need now or shortly.  

Top 5 Udemy Courses to Learn System Design and Software Design in 2023 - Best of Lot

Hello guys, if you are preparing for technical interviews for Software Engineering job then you may be aware of  Software Design or System design. It is one of the most important but at the same time very tough topic to master and many programmers even experienced developer struggle to solve System design problems during interview, particularly while interviewing with top tech companies like Google, Meta, Amazon, Apple, Microsoft, Netflix etc, popularly known as FAANG. If you are also preparing for programming job interview and looking for best System design and Software design resources then you are at the right place. Earlier, I have shared best System Design Books, System Design Questions and best Places to learn System Design and in this article, I am going to share best System Design Interview courses from Udemy, one of my favorite place to learn programming and technical stuff. 

The 2023 Deep Learning RoadMap

Hello guys, if you want to learn Deep Learning and looking for a complete RoadMap to find out all essential skills, tools, and technologies a professional Deep Learning expert should know then you have come to the right place. Earlier, I have shared The 2023 Python Programmer RoadMap, The 2023 Machine Learning RoadMap and Data Engineering RoadMap and in this article, I am going to share with you The 2023 Deep Learning RoadMap. You can consider the deep learning field as a subset of machine learning that uses neural networks to gain experience from the data instead of the built-in algorithm in machine learning. The application of this field is endless. You can make computer vision applications, understand the human language, translate languages, and more. This article will help you become a deep learning engineer step by step.

Top 7 System Design and Software Analysis and Design Books in 2023 - Best of Lot

Hello guys, System design and Software design are two important topic for coding interviews and also two important skill for Software developers. Without knowing how to design System you cannot create new software and it will also be difficult to learn and understand existing software and system. That's why big technical companies like FAANG pays special attention to System design skill and test candidates thoroughly. If you want to learn System design and looking for best resources like best System design books and courses then you have come to the right place. Earlier, I have shared best System design online courses, as well as Software architecture courses,  and common System design questions and in this article, I am going to share with you best System design books to learn Software design. 

ByteByteGo Review - Is ByteByteGo System Design Interview Course by Alex Xu worth it in 2023?

Hello guys, if you are preparing for System Design Interview then you may have come across names like ByteByteGo, Alex Xu or System Design Interview – An insider's guide book by Alex Xu, and if you are wondering what they are or you know about them but thinking whether ByteByteGo is worth it or not? then you have come to the right place. In this article, I will provide my detailed review and opinion on ByteByteGo and his popular System Design Interview  - An Insider's guide book. Though, if you are in hurry and just need a second opinion, I suggest you to go for it. The value Byte Byte Go course provides is much more than the price you pay. It's one of the most comprehensive, up-tp-date, and easy-to-learn System design course I have come across and I highly recommend it to every Programmer and Software Engineer, irrespective of whether you are preparing for System Design Interview or not. It will help you to become a better developer in quick time. 

Top 10 System Design, Software Design, and OOP Design Courses from Educative in 2023 - Best of Lot

Hello guys, if you are preparing for System Design Interview and looking for best resources then you have come to the right place. Earlier, I have shared best System design book, courses, and System design interview questions and in this article, I am going to share in-depth System design courses from Educative.io, a text based online learning platform for developers and engineers. These are the best online courses to prepare for System Design Interviews in 2023.  If you have been doing Software development then you know that System design is one of the most important skill for developers and managers. System Design and Software Design are not just a tool pass interviews but it's the way we build modern Software and that's why a good knowledge of System design is required to become a better Software Engineer. 

Top 8 Courses to Learn about NFTs (Non Fungible Tokens) in 2023 - Best of Lot

Hello guys, if you want to learn what is NFT or Non Fungible Token and what is the buzz around NFT, and have questions like should you create and sell NFT etc then you have come to the right place. Earlier, I have shared best online courses to learn Blockchain and crypto currencies and in this article I am going to share best online courses to learn NFTs, but before that, let's understand what is NFT?  NFTs or else known as Non-Fungible Tokens are a form of digital art. Non-Fungible basically means that they are unique. If you own one NFT, there’s nothing else in this world that is the same as yours. Nothing! That uniqueness and sense of ownership is driving crazy sales with recent reports suggesting that NFT sale clocking at around $70 million and increasing exponentially.

jQuery Tutorial - How to modify multiple HTML elements in one line? Example

jQuery allows you to modify multiples elements in one go, you can modify attributes, text, or color of multiple HTML elements by executing just one line of jQuery code. In this jQuery tutorial, I will show you how to modify multiple <li> elements in one go. In our example, we have a couple of <li> tags to display sub-headings, now we will change them in one go using jQuery. If you look at our HTML, we have an ordered list <ol> to display the top 10 programming languages, each of them is an <li> item. We also have one button, "Click Me", which will when clicked, change all <li> item's text to "jQuery is the new Boss". Here is the jQuery code, which does that.

7 jQuery Selectors Examples for Beginners - Tutorial

jQuery selectors are like CSS Selectors, which allow you to find or select an element from the DOM tree. When HTML pages loaded in a browser like Chrome, Firefox, or Internet Explorer, the browser creates a tree-like structure is known as Document Object Model or DOM. JavaScript and jQuery allow you to play with this DOM i.e. selecting elements from DOM, traversing through DOM, going from one element to another, selecting a list of elements from DOM, adding or removing elements from DOM, etc.

Top 10 Free Courses to learn Spring Framework and Spring Boot in 2023 - Best of Lot

Hello guys, if you want to learn Spring Framework and looking for best online resources like books, courses, and tutorials then you have come to the right place. Earlier, I have shared best Spring Framework courses, books, and Spring interview questions and in this article, I am going to share best free courses to learn Spring framework in 2023. When I shared the list of best Spring Courses, a lot of you asked me about free spring courses and this article is the result of that research, but before we get to the 10 best free Spring courses that are perfect for beginners, let me tell you more about what the Spring Framework really is.

Top 16 Lambda Expressions and Stream API Interview Questions Answers for Experienced Java Programmers

For a long time my readers were asking about some Java 8 interview questions, particularly on lambda expression, streams and around language changes e.g. default methods, method reference and functional interface. Finally, I am able to put some common Java 8 interview questions on lambda expression and Stream API and essential functional programming concepts like map, flatmap, and reduce together, which I going to share with you in this article, but before that, let's talk a little bit about impact of Java 8 in Java Developers interviews and why it's imperative for Java programmers to learn Java 8, particularly Lambda and Stream API. 

How to find all unchecked checkboxes from a page using jQuery? Example Tutorial

Hello guys, In the last tutorial, you have learned how to get all the checked checkboxes from a page using jQuery, but sometimes you also need all the checkboxes which are not selected. In this tutorial, you will learn that. If you remember, we have used the:checked pseudo selector to get all checked checkboxes, but, unfortunately, there is nothing like the :unchecked selector in jQuery, so using that will result in the syntax error. Even the!:checked or :!checked will not work, instead, you need to use not() jQuery selector, which does the negation job.

How to find a Good Programmers on Tech Interviews?

When it comes to interview, goal is to find the most suitable developer for job to get done but its very difficult to judge someone's caliber, experience and expertise in short duration of Interview. There is always a process starting from phone interview, written tests to face-to-face interview, but its still difficult to hire the right programmer. Process can help you to filter candidates but eventually it will come down to your experience and gut feeling. As you take more and more interviews, you will know what to ask and what not and like many other interviewers in the world, you will develop some of your own tips. Similarly, I have developed couple of tips from my experience which has helped me to differentiate an average programmer with a good programmer in past.

Top 5 Courses to Learn Recursion for Dynamic Programming in 2023 - Best of Lot

Hello guys,  if you want to learn and Master Recursion and looking for the best resources like books, online courses, and tutorials then you have come to the right place. Earlier, I have shared the best dynamic programming courses, and 15 Recursion exercises for beginners, and today, I am going to share the best courses to learn Recursion for beginners. Recursion is the process by which a function calls itself again and again directly or indirectly. These types of functions are called recursive functions. All successful software programmers need to have an understanding of how recursive functions work as well as how to build recursive functions. 

Top 10 Dynamic Programming Problems from Coding Interviews

Dynamic Programming is one of the toughest concepts to master for programmers but at the same time, it's quite important to crack any programming job interviews. Nowadays, you will find at least one Dynamic programming coding problem on every coding interview and that's where most of the programmers get stuck. They try to solve the problem using techniques like divide and conquer but ultimately fail because it's difficult to come to a solution to such problems unless you have solved a decent number of dynamic programming-based coding questions. This is very similar to system design questions which look easy but when you try to solve them you often find yourself stuck and that's why I suggest you practice as much as possible. 

Top 10 Java SE 17 Certification Practice Questions and Mock test for 1Z0-829 Exam - Free

Hello guys, if you are preparing for 1Z0-829 certification exam to become a Oracle certified Java SE 17 Developer in 2023 and looking for practice question for preparation then you have come to the right place. In this article, I am going to shared 10 Java SE 17 Practice question from my new Udemy course. It's been a long time since I released any course on Udemy and today, I am excited to announce the launch of my new course - Java SE 17 Mock Test for the 1Z0-829 Exam. I have been working on this course for a long time, ever since this exam was announced and if you follow me on Twitter then you know that as well. If you want to become a certified Java developer in 2023 then you can join this course on Udemy and prepare well to pass this prestigious exam and become  Oracle Certified Java SE 17 developer in 2023.I have spent a lot of time making this course as best as possible to help prepare for this exam and learn Java better.

Top 17 Debugging Interview Questions for Experienced Java Programmers

Hello guys, if you are a beginner or an experienced Java developer with 1 to 3 years of experience under your belt, when you go for a Java interview you should prepare some Java debugging interview questions like how to debug a Java program running in Linux environment etc. In the past, I have shared 130+ core Java questions, 50+ Multithreading Questions, 25+ Java Collection questions and 50+ Lambda and Stream interview questions and in this article, I am going to share 17 questions to test debugging skills of Java programmers. These are the questions which I have seen during my own interview as candidate and also asked as Interviewer and there is chance that you may have also seen it on your interview.

How to Fix 'javac' is not recognized as an internal or external command in Windows and Linux? Example

Hello guys, if you are trying to compile your Java source file and getting "'javac' is not recognized as an internal or external command" in Windows or Linux machine like Windows 10 or Redhat 8 but not sure what to do then you have come to the right place. This is a common Java related error and can occur to an operating system like Windows, Mac or Linux if java is not installed properly like only JRE is installed and JDK is not installed or javac is not added on PATH environment variable. In this article, I will explain what this error is and how you can fix it by following step by step guide I share, but if you still cannot solve this problem on your own then just ask for help in comments. But don't forget to check your PATH environment variable because that's where JDK/bin directory needs to be present, which contains all Java related commands including "javac" and "java" which are used to compile and run Java applications.

10 Essential Git commands Every Java Developer Should Know

Hello guys, if you are a Programmer you probably have heard about Git, well most of you might have already been veteran into Git and don't need any more articles and tutorials, but if you are a beginner then Git is one of the most important skill to learn. If you are a Computer Science graduate, a Software Engineer, or even a Student trying to learn Programming on your own, Git is a must-know skill for you. If you already know the importance of Git and looking for best resources to learn Git then you have come to the right place. Earlier, I have shared best free Git courses and best places to learn Git and in this article, I am going to share examples of essential git commands which every programmer should know.

Top 5 Spring and Hibernate Training Courses for Java JEE Programmers - Best of Lot

Spring and Hibernate are two of the hottest and most in-demand web frameworks in the Java world and also two of the most essential skill for any Java programmer to get a job in the web development space. The Spring framework is in around 2004 and established itself as the leading framework to develop Java applications both in core Java and web development areas. The Spring framework comes with a lot of modules to support different kinds of developments like Spring Security to address the security requirements of most web and enterprise Java applications. It supports single sign-on, LDAP authentication, Role-based access control, and much more such essential features. Spring also supports the development of REST services which is now become a standard way to provide web services.

6 Free DevOps Courses for Experienced Developers in 2023 - Best of Lot [UPDATED]

Hello Java Programmers and developer friends, If you are an experienced developer and want to become a DevOps Engineer or just want to learn the DevOps process and tools to improve your development and delivery process and looking for free DevOps online courses to kickstart your journey, then you have come to the right place. Earlier, I shared the best DevOps books and training courses, and today, I will share the best free online lessons to learn about DevOps. These free courses are created by experts and trusted by thousands of developers and they will teach you DevOps concepts, practice, DevOps tools like Docker, Jenkins, Ansible, and Kubernetes and suitable for both beginners and experienced developers. They are also curated from popular online learning platforms like Udemy, Pluralsight, and Coursera, and they offer practice and hands-on training.

3 ways to learn React Native for App Development in 2023

Hello guys, if you want to learn React Native for Application development but not sure how to learn and where to start then you have come to the right place. Earlier, I have shared best React Native courses and App development tools and technology and in this article, I am going to share best way to learn React Native in 2023, by reading books, joining online course and building projects. Mobile application development has advanced immensely in the last decade. Along with the web, demand for mobile applications has increased tremendously. Moreover, web applications are created by keeping the “Mobile-first approach” in mind.

How to Learn Python Programming and Development in 2023?

If you want to learn Python Programming language online in a week on your own and looking for the best online Python resources then you have come to the right place. In the past, I have shared the best Python courses, books, Python developer RoadMap, and tutorials, and today, I am going to share with you the exact step-by-step plan to learn Python programming from scratch in 7 days by joining the best Python courses on Udemy, one of my favorite and most affordable website for online learning. After thorough research, combined with my own experience, I have chosen two of the best Python Bootcamp courses which can be used to learn Python from scratch in a week's time.

Top 5 programming Languages for Artificial Intelligence in 2023 - Best of Lot

Hello guys, if you want to do AI Development or want to create Artificial Intelligence based apps and looking for best programming language then you have come to the right place. Earlier, I have shared best programming language for web development, app development, and data science development and today, I am going to share best programming language for AI Development. All programming languages are not created equal. Only a handful of programming languages remain and serve the community out of countless. The programming languages we'll be discussing presently have stood the test of time. For decades, they've been used for a variety of undertakings.

Top 5 Websites to Learn System Design and Software Design in 2023 - Best of Lot

Hello guys, if you are preparing for System design Interview and looking for best resources to master Software design and System design then you have come to the right place. Earlier, I have shred best System Courses, Books, and System Interview Questions and in this article, I am going to share best places to learn System design in 2023. Before we get to the best websites that will teach you everything you need to know about system design, let me tell you a little bit about what it really is. Systems design is basically the process of defining elements of a system including modules, architecture, components, interface, and data for a system based on a specific set of requirements. It can also refer to the process of defining, developing, and designing systems. These designs have to satisfy the specific needs of a company or an organization.

Whizlabs Review - How to Learn Docker, Kubernetes, AWS, Azure, and Google Cloud Platform using Hands-on Labs?

Hello guys, Cloud computing is rapidly becoming one of the essential skill for all kind of developers and no matter what you will need to learn Cloud Computing if you want to remain marketable. I learned this truth couple of years ago and since then spent a lot of time learning AWS, Azure, Kubernetes, Docker, and Google Cloud Platform. The big problem with learning Cloud computing and different cloud platform like AWS and Azure is that you cannot learn them by reading books or watching course. You need real, hands-on practice which can only be possible by either using the free tier of respective platform or using hands-on labs like the one provided by Whizlabs and QwikLabs. 

10 Data Structures Every Programmer Should Learn (with Practice Exercises)

Data Structure and Algorithms are two pillars of Programming. You may know that "Data Structure + Algorithms = Computer Program". They are also the most important ingredient of a good program and right choice of Data Structure and Algorithms can improve performance drastically, whereas a wrong choice can spoil the party, but do you know what exactly they are? Well, Data Structure are nothing but a way to store data, while Algorithms are ways to operate on that Data. There is a reason why Data Structure and Algorithms are taught in every single Computer Science classes, it doesn't matter whether you are learning Java, C++, Python, JavaScript, Golang, or any other programing language, those data structure and algorithm will be same everywhere. 

Coursera Plus Review - Should you Learn on Coursera in 2023? It it worth it?

Hello guys, As a programmer, we always need to learn new skills, frameworks, technologies, and libraries, and we often end up buying so many courses for that; I know people who have more than 300 courses on Udemy and other online courses platforms, but Coursera now has a better way, Coursera Plus. This is a subscription plan for Coursera courses and specializations, which will provide you access to their 7000+ courses, guided projects, specialization, and professional certificates with just one subscription. It costs around $390 per year or $59 per month, which may sound more than other subscription and membership online learning portals like Pluralsight, Educative, and CodeCademy, but Coursera provides certificates and courses worldwide reputed universities which no one else.

How to fix java.lang.OutOfMemoryError: unable to create new native thread in Java [Solution]

It's been a long time since I shared any Java Error or Exception troubleshooting tutorial so here we are. In this post, we will take a look at the "java.lang.OutOfMemoryError: unable to create new native thread" error which is a rate but quite possible in multithreading Java applications. This is another Java OutOfMemoryError that comes when JVM hits the native thread limitation allowed to be open by one process and not able to create any more new threads. Since each Java thread is associated with the OS thread, when OS refuses to provide a new thread, JVM throws OutOfMemoryError. It's rarely you will see common Java applications throwing this error but it's common when multiple application is using the same Java process e.g. Web Server Tomcat and a significant number of threads are allocated due to high load.

How to display full command a Running Process in Linux and Solaris? Example

One of the problems with ps command, which is a popular tool to find any processes along with the grep command in the Solaris operating system is that it doesn't show full command-line argument of process. This means if you are doing grep on any text which appears at the tail end of the long command line, you will likely not able to capture that process by using ps and grep. This is dangerous because it may lead you to assume that certain process is not running and you may restart it again, despite its being running and only because you didn't find the process.

Top 2 System Design Interview Question from Investment Banks? Limit Order Book Example

No doubt that Data structure and algorithms are an integral part of any Programming job interview, including Java, C++, or any other programming language. In fact, Data structure and algorithms are quite a favorite one and all top-notch companies including Google, Microsoft, Amazon, and investment banks like Goldman Sachs, Citigroup, Barclays, Morgan Stanley or J.P. Morgan focus extensively on data structure and algorithms while hiring both senior and mid-level developers in Java, C++, and C# positions.

Top 50 Linux Interview Questions Answers for 3 to 5 Years Experienced

Linux is the #1 operating system for hosting real world production application. Most of the real world Java application in big IBs are hosted on RedHat Linux. This makes Linux an extremely important skill for getting a Job. Along with any programming language e.g. Java or C++, you must have good command on Linux and SQL to get a programming job. Btw, Linux is not just limited for development job but it is even more important for support roles and system admin jobs. If you are working in production support then an excellent knowledge of Linux is expected from you, which includes knowing fundamental of Linux e.g. how Linux OS works?, what is kernel or shell?, or what is init process?, as well as good knowledge of various Linux commands to perform day-to-day job, and troubleshoot any production issues. 

50+ Java Collections and Generics Interview Questions and Answers

Hello guys, If you are preparing for Java interviews then you may know that Java Generics and Collections are two of the most important topics, particularly Generics where some of the trickiest Java questions can be asked. They are also used to gauge your experience and depth of your Java knowledge, hence it's imperative for both beginners and experienced Java programmers to prepare this topic well. While the Java Collection framework provides an implementation of some command data structures like List, Set, Array, Hash table, Queue, Stack, PriorityQueue, etc, Generics provides Type safety.

How to update value in ConcurrentHashMap atomically in Java? Compute and ComputeIfAbsent Example

Hello guys, if you have been doing Java development then you know that Java 8 brings a lot of changes not just on programming language part by introducing Lambda expression, default methods on interface, static method on interface but also on API  and SDK part like Stream API and new Date and Time API. But while those bigger changes get lot of coverage many small changes but very useful in day to day programming task doesn't get enough mention and many Java programmers are unaware of those. One of such enhancement was addition of compute(), computeIfAbsent(), and computeIfPresent() method in java.util.Map interface. Adding  a new method on an existing interface was not possible before Java 8 but new feature like default and static method on interface made it possible and Java designers take full advantage of these two feature to enhance and improve existing interface like Collection and Map.