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10 Examples of Kubectl command in Kubernetes in Windows and Linux

Hello guys, if you are working with Kubernetes pods like deploying your application, starting and stopping them by scaling to zero instances, while you just want to see logs or want to login into the Kubernetes pods itself, you must know how to use kubectl commands to do all these task. Since most of the companies, both big and small are using Kubernetes to deploy services on cloud, its imperative for Java developers and other Software developers to get familiar with the kubectl command. We deploy our Java Microservices on Kubernetes mainly because Kubernetes can start the services automatically when it goes down. We have different Kubernetes clusters for different environments like DEV, UAT, and PRODUCTION and I often switch between those cluster using kubectl commands to check the status of our Java services or interact with them.

21 Jenkins and CI/CD Interview Questions for Java Developers and DevOps (with Answers)

Hello guys, if you are preparing for Java developer interview or a DevOps Engineering interview then you must prepare for Jenkins related interview questions. Jenkins is one of the most essential tool for creating build, test, and deploy pipelines in Java world and almost every company and project you work will need a Jenkins pipeline for automation. If you are joining as junior developer then most likely you will already find the pipelines setup for you and you only need to customize it or modify based upon new requirements but if you are joining as an experienced developers or DevOps Engineer and its a green field project then you will most likely need to do all the hard work and setup those Jenkins  pipelines from scratch, and its not possible without a good, solid knowledge of how Jenkins works and different plugins.

8 ways to Sort List in Java 8 using Lambda Expression + Method Reference - Example Tutorial

Hello guys, as a Java developer we often need to sort List like ArrayList, LinkedList, or CopyOnWriteArrayList and while I have share many articles on sorting a list in Java in both increasing order  and deceasing order as well as sorting ArrayList in a custom order using Comparator, things have changed a lot in Java world, especially after Java 8 when Lambda expression and method reference was first introduced. Now there are more declarative and expressive way to sort a List of object in different order based upon different conditions. Enhancements made on Comparator API has also made comparing and sorting object in Java much easier and I have shown the power of new Comparator API in my earlier article about advanced Java Comparator example. I was particularly impressed with comparing() and thenComparing() as they literally make comparison on multiple condition easier. 

50 Free Spring Framework Practice Questions Answers for VMWARE EDU-1202 Certification Exam

Hello guys, preparing for IT certification like Oracle's Java certification or Vmware's Spring Certification required a lot of hard-work. I have seen many experienced Java developers failing these certifications and losing money and time due to over-confidence and lack of preparation. A structured and complete certification preparation involves reading books, joining course and doing practice questions. When it comes to Spring certification, practice questions are quite hard to find and that's why I created my Udemy course with 250+ Spring Certification questions. This course has helped more than 9000 students in their Spring certification preparation journey. 

Top 5 Courses to Learn SQL and Database in 2022 - Best of Lot

Hello guys, if you are a computer science graduate or new to the programming world, interested in learning SQL, and looking for some excellent resources, like books, courses, and tutorials to start with, then you have come to the right place. In the past, I have shared some of the best SQL books and tutorials, and today I am going to share some of the best SQL and database courses to learn and master this useful technology. If you don't know what SQL is and why you should learn it, let me give you a brief overview of SQL for everyone's benefit. SQL is a programming language to work with a database. You can use SQL to create database objects, like tables, stored procedures, etc., and also to store and retrieve data from the database.

Top 5 Free Multithreading Courses for Beginners and Experienced Java Programmers in 2022 - Best of Lot

Hello guys, if you want to learn multithreading and concurrency in Java and looking for best free resources like online courses and tutorials then you have come to the right place. Earlier, I have shared best free Java Courses and best free Spring Framework courses and today, I will share best free online courses to learn Multithreading and Concurrency in Java. Multithreading is one of the important skill for Java programmers as companies are always in hunt of Java programmer who are good at multithreading and concurrency but at the same time its very hard topic to master. Acquiring solid multithreading and concurrency skill require a lot of hard worked and years of experience but you can speed up by joining best Java multithreading courses and learning from expert.

How to return JSON, XML or Thymeleaf Views from Spring MVC Controller? Example Tutorial

Hello guys, if you are working in Spring based web application and you wan to return JSON, XML, or Thymeleaf View from your application but don't know how to do that then you have come to the right place. Earlier, I have shared how to create REST API in Spring, React + Spring project, and Spring Boot Interview Questions  and In this tutorial we are going to discuss, how to return to JSON, XML, or Thymeleaf view from the Spring MVC controller. To ensure that your payload from the MVC endpoint, ensure your project is using the Spring Boot starter web. You can use the following dependency to include spring boot starter web in your project. 

Template Method Pattern in Java? Example Tutorial

Template Method Pattern defines a sequence of steps of an algorithm. The subclasses are allowed to override the steps but not allowed to change the sequence. It can also be provided a default implementation for one or more steps. Let us look at the following example to understand Template Method Pattern.  A Template method pattern provides a skeleton for performing any sort of algorithm or an operation, and it allows the sub-classes to re-define part of the logic. One of the key advantage of Template pattern is that its natural fit for building frameworks, so that parent framework classes can make callbacks into methods implemented in children. Spring Framework makes full examples of Template pattern and you will find several key classes like JdbcTemplate, RestTemplate, and JmsTemplate which are created using Template pattern.

What is Spring Expression Language (SpEL)? Difference between $ and # in @Value expressions Example

Hello Java programmers, if you are wondering what is Spring Expression Language and how to use them in your Spring Framework or Spring Boot application then you have come to the right place. Earlier, I have shared the best Spring Framework coursesFree Spring Questions, Spring projects, and books, and in this article, I am going to teach you about Spring Expression Language with simple, easy-to-understand examples. The Spring Expression Language (SpEL for short) is a powerful language that supports querying and manipulating an object graph at runtime. The syntax is similar to Unified EL, but it has several more features, such as method calling and rudimentary string templating.

Top 23 Object Oriented Design Patterns (GOF) Java Programmers Should Learn

Design Patterns are tried and tested way of solving a problem within a given context. They are not invented, rather they are discovered, which is also obvious by use of word pattern. By using design pattern, you take knowledge of all wide communities and can safely use it to solve that problem. At times they might not give you perfect solution, require bit of tweaking, but they certainly provides one of the best solution, as long as you use them properly. While doing object oriented development, they are numerous task which appears quite often e.g. creating objects, structuring code, and implementing different behaviors based on different context.

Student Management System Project - FullStack Java + Spring Boot + React.js Example Tutorial

Hello Java programmers, if you want to learn Spring Boot and Reactjs and looking for a full-stack Java example or a mini project then you have come to the right place. Earlier, I have shared the best Spring Boot coursesbooks, and best reactjs courses as well as many courses to learn full-stack development in Java and become a full-stack java developer. In this mini project, you will learn how to create an application that is capable of creating, deleting, updating, and retrieving functions using the Spring Boot, React, and H2 Database. In this tutorial you will create a School Classroom Application that can insert, update, delete and search students. The frontend of the application is developed using Reactjs and also the backend is developed using spring boot. And, most importantly communication between the two platforms will be done using the REST APIs. 

How to merge two HashMap in Java 8 - Map.merge() example

You can merge two Map in Java using the newly added merge() function in Java 8. This allows you to copy values from one map to another to merge both of them. It also provide a lot of flexibility to handle duplicate keys. In the last article, I have shown you how to combine two Map in Java using the putAll() method but there was a problem. If a key is present in both map, then putAll() overrides the value from the second map, which you may or may not want. The real issue is that you don't have any control on what should happen if there exists duplicate keys in those Map e.g. you may want to keep the original value intact or you always want values from second map to override values in first map, or you just want to concat or add two values to form a new value. This problem is solved by the Map.merge() method in JDK 8, which allows you to pass a lambda expression to control the remapping operation.