Чашечка Java

Движение по магистрали без аварий. Или как передавать 1,5 терабайта в сутки и ни одного не потерять? Привет, Хабр. Меня зовут Владимир Евсеев, я Senior Java developer, Teamlead в SSP SOFT. Наша команда приступила к масштабному проекту: системе, обеспечивающей транспортный уровень документооборота банка. Сегодня я расскажу, как мы справились с первым этапом: выстроили магистраль, способную передавать около 150 000 файлов в сутки, или 1,5 терабайта информации. Поделюсь, что получилось и что еще предстоит  довести до совершенства. Читать: https://habr.com/ru/post/710770/?utm_campaign=710770

What is CQRS - Command Query Responsibility Segregator Pattern in Java? Example Tutorial Hello guys, if you are wondering what is CQRS pattern and when and how to use it in your Microservices then you have come to the right place. CQRS is one of the 10 essential Microservice pattern and can be used when your application is either read heavy or write heavy and reading and writing requirement are very different. It aims to separate your app into two parts, command part which writes data and query part which read data and that's how it allows you to develop, scale and optimize them separately. It's also one of the popular Microservices Questions and if you are preparing for interviews, you should prepare this pattern as well. Earlier, I have explained SAGA Pattern and Database Per Microservice pattern and in this article I will explain CQRS pattern, when to use it and what problem does it solve. Java Interview questions and tutorials Read: http://www.java67.com/2023/01/what-is-cqrs-command-query.html

10 examples of crontab commands in Linux Hello guys, if you are working in Linux or UNIX environment and scheduled any job or script to run at a particular time at everyday like a script to archive log files at midnight or a script to restart your app on Monday morning then you must have come across crontab commandin Linux. While there are many solution to schedule jobs in enterprise application like Control M from Bmc Software and AutoSys but the crontab command provides the easiest way to schedule any script in Linux, as you don't need any third party software for scheduling. It's also quite popular, so much so that all the jobs scheduled by crontab is called cron jobs, and that's why I think every developer should know about crontab command and how to use it. Java Interview questions and tutorials Read: http://www.java67.com/2022/08/10-examples-of-crontab-commands-in-linux.html

When to use PUT or POST in a RESTful API and Web Service? Answer Hello guys, if you are confused about whether to use PUT or POST for updating a resource using RESTful web service then you have come to the right place. In the past, I have shared the best RESTful web service books and courses and today, I am going to share some tips to choose between PUT and POST while designing your RESTful web services. Btw, you are not alone, one of the most common confusion among web developers is the choice of PUT or POST HTTP method for creating and updating a resource while developing RESTful Web Services. Since both can be used to submit data, you can use either POST or PUT to create or update a resource. Java Interview questions and tutorials Read: http://www.java67.com/2016/09/when-to-use-put-or-post-in-restful-web-services.html

10 Examples of New HttpClient + HttpRequest + HttpResponse In Java 11 (REST Client] Hello guys, one of the notable addition in recent Java release is the full fledged HttpClient from Java. This is one of the class or utility which was much needed in Java. It was quite surprising that JDK doesn't have any fully functional HTTP client to connect to REST APIs in this world of API Integration. Until Java 11, Java developer rely on classes like RestTemplate and WebClient from Spring Framework to make HTTP class to REST APIs, but now you don't need to include Spring Framework in your project just for that. You can now use HttpClient classand its support classes like HttpRequest and HttpResponse to make both synchronous and asynchronous HTTP calls in Java. Java Interview questions and tutorials Read: http://www.java67.com/2022/12/10-examples-of-java-httpclient.html

Java + Spring Boot + Microservices Example - Step by Step Guide Hello guys, if you are wondering how to create a Microservice in Java and Spring Boot then you are ar the right place. In the past, I have shared best Spring Boot courses for Microservices, Interview Questionsas well as essential Microservice design principles and patternslike circuit breaker, CQRS, Event sourcing etc and In this article, we will cover the fundamentals of microservices with Spring Boot utilizing Spring cloud. We will cover a few fundamental ideas and then we will make a little micro-service to give you an outline. I will also share step by step guide to make Microservices in Java and then deploy them using Docker and Kubernetes on Cloud. Java Interview questions and tutorials Read: http://www.java67.com/2022/08/java-spring-boot-microservices-example.html

[Solved] java.lang.ClassNotFoundException: org.Springframework.Web.Context.ContextLoaderListener in Java and Spring Problem :You are getting java.lang.ClassNotFoundException : org.Springframework.Web. Context.ContextLoaderListener in your Spring-based Java Web application. Cause: This error comes when you are using the Spring MVC framework in your Java Web application and configured org.springframework.web.context.ContextLoaderListener as a listener in your deployment descriptor also known as web.xml, but the JAR which contains this class is not available in the web application's CLASSPATH. Java Interview questions and tutorials Read: http://www.java67.com/2015/06/org.Springframework.Web.Context.ContextLoaderListener.html

How to fix org.springframework.beans.factory.BeanCreationException: Error creating bean with name X [Java Spring] If you are using the Spring framework in your Java application and getting this error during startup it means Spring is not able to initialize the bean X and add it into its application context, Why? There could be multiple reasons like a typo on the spring bean name. Let's take a closer look at the stack trace to find out the real reason: BeanInstantiationException: Could not instantiate bean class [X]: No default constructor found; nested exception is java.lang.NoSuchMethodException: X.() Here X is the class, which is declared as Spring bean. The error clearly says that the default constructor is not present in class X. Java Interview questions and tutorials Read: http://www.java67.com/2017/07/solving-orgspringframeworkbeansfactoryb-beancreation-exception-java-spring.html

10 Git Commands Every Programmer Should Learn In 2023 (with ChatGPT Examples) Hello guys, Git is one of the most important skill for programmers, developers and data scientist and if you don't know git then you will struggle working in a team. If you want to learn Git in 2023 then you can start with these essential Git commands. I have explained the command and give you example. For examples, I have asked ChatGPT to see how it explains and I was amazed to see the response so I have included here for my own reference. I don't if ChatGPT will remain free forever but I am taking screenshot for the questions which I am asking so that I can keep a record for myself and you in future as ChatGPT is the best instructor I have got today and its helping me to learn and revise several key concepts. Java Interview questions and tutorials Read: http://www.java67.com/2023/01/10-git-commands-every-programmer-should.html

Difference between Serializable vs Externalizable in Java - Interview Question Serializable vs Externalizable What is the difference between Serializable and Externalizable in Javais famous core Java interview questions and for some of them its one of those difficult Java question, which no one wants to see in Java interview. I was in that category until I read Effective Java and explored How Serialization works in Java and find out more about the Serialization process. What makes Serialization questions tricky is, Serialization as a persistence mechanism is not very popular. Many programmers prefer databases, memory-mapped files, or simple text files over Serialization. But Serialization has a distinguished advantage over these mechanisms. Java Interview questions and tutorials Read: http://www.java67.com/2012/10/difference-between-serializable-vs-externalizable-interface.html

What is ContextLoaderListener in Spring MVC? Example Tutorial The ContextLoaderListner is one of the essential components of the Spring MVC framework, probably the most important after the DispatcherServlet itself. It is used to create the root context and responsible for loading beans, which are shared by multiple DispatcherServlet like beans related to the service layer and data access layer. In general, When you develop Spring MVC based web applications and also using Spring in the services layer, you need to provide two application-contexts. The first one is configured using ContextLoaderListener, and the other is set using DispatcherServlet. The DispatcherServlet is responsible for loading web component-specific beans like controllers, view resolvers, and handler mappingswhile, as I said before, ContextLoaderListener is accountable for loading middle-tier and data-tier beans which forms the back end of Spring applications. Java Interview questions and tutorials Read: http://www.java67.com/2019/05/contextloaderlistener-in-spring-mvc-10.html

What is the use of DispatcherServlet in Spring MVC? Interview Question Example Hello guys, In today's article we are going to discuss one interesting and the important Spring MVC concept, which is also a popular Spring Interview question. How DispatcherServlet works internally in Spring MVC or What is the role of DispatcherServlet in Spring MVC are some of the frequently asked Spring MVC Interview Questions. You might have seen them already during your previous Java web development interviews but if you have not, it's a good question to know. In this article, I'll answer these questions by explaining What is DispatcherServlet and its importance in Spring MVC. The DispatcherServlet is one of the important components of the Spring MVC web framework and acts as a Front Controller. Java Interview questions and tutorials Read: http://www.java67.com/2017/06/what-is-use-of-dispatcherservlet-in-spring-mvc.html

Top 15 Spring Data JPA Interview Questions with Answers Hello guys, If you are preparing for a Spring developer interview and looking for some Spring Data JPA Interview questions then you have come to the right place. Earlier, I have shared frequently asked interview questions on Spring Boot, Spring Cloud, Microservices, and Spring MVC in general, and in this article, I will share frequently asked Spring Data JPA Interview Questions with Answers for Java developers. Spring is one of the most popular and widely used frameworks. Spring Data JPA is an important part of the framework as it makes working with JPA or any JPA implementation like Hibernate easier. Java Interview questions and tutorials Read: http://www.java67.com/2021/01/spring-data-jpa-interview-questions-answers-java.html

Top Java Blogs Weekly: Best of 3/2023 Best of Top Java Blogs, year 2023, week 3 Read: https://www.topjavablogs.com/news/best-of-3-2023

Сортировка слиянием через рекурсию В данной публикации мы продолжим применять рекурсию на практике и напишем код сортировки слиянием, а также разберем, как работает данный вид сортировки. Читать: https://habr.com/ru/post/710620/?utm_campaign=710620

Difference between @Component, @Controller, @Service, and @Repository Spring Annotations - Java Hello guys if you are wondering what is the difference between @Component, @Controller, @Service, and @Reposistory annotation in Spring Framework then you have come to the right place. In the past, I have shared 15 Spring Boot Interview Questions and 30 Spring MVC questions and in this article, I am going to answer the fundamental and popular Spring questions about @Component, @Controller, @Service, and @Repository annotation, but before we go into differences, let's understand the similarity first. Java Interview questions and tutorials Read: http://www.java67.com/2022/06/difference-between-component-service-repository-in-spring.html

JavaScript, Java, and Python skills top demand Read: https://www.infoworld.com/article/3685672/javascript-java-and-python-skills-top-demand.html#tk.rss_java

Spring Modulith: достигли ли мы зрелости модульности Одной из основных причин разработки микросервисов является то, что они обеспечивают четкие границы модулей. Однако минусы микросервисов настолько огромны, что это все равно, что отрубить себе правую руку, чтобы научиться писать левой; есть более управляемые (и менее болезненные!) способы достижения того же результата. Даже с тех пор, как началось повальное увлечение микросервисами, возобладали некоторые более хладнокровные. В частности, Оливер Дротбом, разработчик среды Spring, долгое время был сторонником альтернативы moduliths. Идея состоит в том, чтобы сохранить монолит, но спроектировать его вокруг модулей. Многие выбирают микросервисы, потому что приложение, над которым они работают, напоминает блюдо со спагетти. Если бы их приложение было лучше спроектировано, притяжение микросервисов не было бы таким сильным. Читать: https://habr.com/ru/post/701984/?utm_campaign=701984

Telegram-бот счётчик сообщений на Java и Spring Boot Пишем простой Телеграм-бот на Java, который будет подсчитывать сообщения от пользователей чата и записывать их в БД через PostgreSQL. Читать: «Telegram-бот счётчик сообщений на Java и Spring Boot»