Чашечка Java

Зачем нам Reactive и как его готовить Привет! Меня зовут Татьяна Руфанова. Сегодня мы будем понимать и принимать Reactive (Реактив). В статье расскажу, почему мы выбрали Реактив в мидл слое мобильного приложения Альфа-Банка (а у нас 300 микросервисов и треть из них реактивные), разберём, почему «нелогичное» поведение реактивной программы на самом деле очень логичное, какие сложности реактивный подход принесёт в процессе написания и исполнения кода, и как с этим бороться. А чтобы не траблшутить в проде, будем ломать тесты на Project Reactor. Налейте чаю, включите звуки природы и настройтесь пройти все стадии принятия Reactive. Читать: https://habr.com/ru/companies/alfa/articles/729020/?utm_campaign=729020

Как заставить Jmeter собирать скриншоты графиков после тестов Привет, Хабр! Меня зовут Илья Улизко, я занимаюсь нагрузочным тестированием ДБО ЮЛ в блоке Цифровой Трансформации «РСХБ-Интех». В этой статье я поделюсь с вами опытом автоматизации сбора графиков в Grafana при отсутствии установленного grafana-image-render плагина на сервере. Для того, чтобы научить Apache Jmeter делать скриншоты панелей в Grafana нам понадобится Selenium и Browsermob-proxy. Читать: https://habr.com/ru/companies/rshb/articles/729196/?utm_campaign=729196

What Java developer Should Know about Object and java.lang.Object Java is an object oriented programming language and core of Java API is java.lang.Object class. In order to work properly in Java platform its important to learn fundamentals of Object in Java e.g. What is an Object in Java and How to use Object in Java. There are two meanings of Object in Java one which is used to refer object of Object oriented programming language or OOPS and other is java.lang.Object class. Every class in Java which explicitly doesn’t extend any class, implicitly extends java.lang.Object class. Crucial methods like finalize and wait and notify are declared in Object class, which is source of one of the java questions Why wait and notify are declared in Object class and not on java.lang.Thread class. Java Interview questions and tutorials Read: http://www.java67.com/2012/12/object-in-java-and-OOPS-example-tutorial.html

Difference between transient vs volatile variable or modifier in Java transient vs volatile modifier in Java What is the difference between transient and volatile variables or modifiers in Javais one of the most common Serialization Interview Questions in Java. Though volatile variables are not related to Serialization at all, this question is mostly asked in conjunction with other Serialization questions. Both transient and volatile modifiers are completely different from each other. In fact, this question is as popular as Serializable vs Externalizable in Java. The main difference betweentransient vs volatile variables is that transient variables are not serialized during the Serialization process in Java while volatile variables are used to provide alternative synchronization in Java. Java Interview questions and tutorials Read: http://www.java67.com/2012/11/difference-between-transient-vs-volatile-modifier-variable-java.html

20 EJB 3.0 Interview Questions and Answers - Java J2EE EJB interview questions are core part of any Java J2EE interview. As EJB forms business layer for modern J2EE enterprise application, Good knowledge of EJB is expected from J2EE programmer. Purpose of these EJB interview questions is to give an Idea about what kind of questions you can expect on J2EE and EJB interviews. EJB was always tough for Java programmer because of heavy weight architecture comprised with many interfaces e.g. home interface, remote interface, local interface, bean class etc. It take too much time and knowledge to implement and use EJB in your Java web and enterprise application forget about challenges posed by application servers like WebLogic or IBM WebSphere. Java Interview questions and tutorials Read: http://www.java67.com/2012/10/20-ejb-30-interview-questions-and.html

Autoboxing, Enum, Generics, Varargs methods - Java 5 Features Quick Overview What is Autoboxing, Generics, Enum and Varargs method in Java 5 Java 5 introduces Autoboxing, Generics, varargs and Enum along with several other features and improvement. It's been few years when Java programming language was enhanced with these features but still Java programmer thing Autoboxing, Enum, Generics or Variable arguments as an advanced feature and afraid to learn them. They are very much part of Java fundamentals just like Abstraction, Inheritance, Encapsulation and Polymorphism are part of Object oriented programming concepts. It's important to understand what are these feature and How to use them, even if you don't use them in your code, you may have to work on someone else code which is written in Java 5 and uses Generics Collection, Autoboxing quite frequently. Java Interview questions and tutorials Read: http://www.java67.com/2012/09/autoboxing-enum-generics-varargs-java-5-features.html

What is Struts Action Class in Java J2EE - How to use What is Action class in Struts Struts in java is a framework, used to make web application its is based on Model View Controller or MVC design Pattern where Model represent the internal state and action used to change the state view represent presentation component and a controller is responsible for receiving the request from the client and decide which business logic should be called. Basically, Struts have different classes to represent this Model, View, and Controller we call them as Action, Action Form, and Action Servlet. So Model – Action classes View - Action form classes Controller – Action Servlet classes In this article, we are focusing on the Model layer of struts framework. Action class is used to provide an interface to application model layer.  What is Action class and how to use Action class is also a popular Struts interview Question asked in various J2EE interviews. Java Interview questions and tutorials Read: http://www.java67.com/2012/09/what-is-struts-action-class-in-java.html

10 Books and Courses to Prepare Technical Programming/Coding Job Interviews If you are preparing for a technical interview in the software development sector and looking for some great books to boost your preparation, then you have come to the right place. In the past, I have hared some of the best online courses to prepare coding interviews. In this article, I am going to share some of the best programming/coding interview books to prepare well for any software development jobs. These books are enough to crack even the toughest of the job interviews at Google, Amazon, or Microsoft. They provide excellent coverage of all essential topics for programming job interviews like data structure and algorithms, system design, algorithm design, computer science fundamentals, SQL, Linux, Java, Networking, etc. Java Interview questions and tutorials Read: http://www.java67.com/2017/06/10-books-to-prepare-technical-coding-job-interviews.html

5 Advanced Books for Experienced Java, C++, Python, Ruby and JavaScript Developers It's one thing to know about the syntax and semantics of a programming language and other things to use it effectively. If you are a programmer and want to take your programming skill to next level in your choice of programming language, and looking for the best resources then you have come to the right place. Earlier, I have shared the best online courses to learn Python, Java, JavaScript, and C++, and today, I am going to share advanced programming books for experienced Java, C++, Python, Ruby, and JavaScript developers. To be honest, there are several books that will be taught you about the syntax and grammar of a programming language, but there are really few books that will teach you the customary and effective ways to use it, also known as idiom and usages. Java Interview questions and tutorials Read: http://www.java67.com/2021/03/advanced-programming-books-for-experienced-developers.html

Is it Possible to take Spring Professional v5.0 Certification without the Official Training course? Just a couple of years ago, It wasn't possible to take Spring Professional certification without a mandatory expensive training course from Pivotal, but from 10th May 2017 onwards, you can take Spring Certification without a training course. Yes, you read it correctly, it's now possible to become Spring certified developer without spending USD 3200 on mandatory Spring training, like the Core Spring training. For years, Pivotal, the company behind the Spring framework (now Vmware) ensured that a Java developer can only get a Spring Professional certification by first going into a 4-day training run by Pivotal and its partner around the world. Java Interview questions and tutorials Read: http://www.java67.com/2017/06/is-it-possible-to-take-spring-certification-without-training.html

Top 5 Books for Java 8 Certifications - 1Z0-808 (OCA) and 1Z0-809 (OCP) If you are preparing for Oracle's Java SE 8 certification then you may know that in order to become a Java 8 Certified developer, you need to pass two exams, the OCAJP 8 exam with code 1Z0-808 and the OCPJP8 exam with code 1Z0-809. You will not be a Java SE 8 certified programmer if you just pass the OCAJP8 exam. In order to prepare for both these exams, you need to choose an excellent study guide, a couple of quality online courses, and a unique mock exam simulator, apart from writing programs on a daily basis. This is the perfect recipe to crack Oracle's Java certification in the first attempt. It requires a lot of hard work but it's worth it. Java Interview questions and tutorials Read: http://www.java67.com/2017/05/top-5-books-for-ocajp8-and-ocpjp8-Java-8-certification-exam.html

Java на стероидах, или опыт работы с Jmix Как после привычного Spring за месяц сделать сайт с платформой быстрой разработки Jmix. Коротко о технологии, особенностях, возникающих в процессе вопросах и ответах на них. Читать: https://habr.com/ru/articles/728896/?utm_campaign=728896

Article: Unleash the Power of Open Source Java Profilers: Comparing VisualVM, JMC, and async-profiler This article conveys the foundational concepts and different types of Open Source Java profilers. It allows you to choose the best-suited profiler for your needs and comprehend how these tools work in principle. The aim of a profiler is to obtain information on the program execution so that a developer can see how much time a method executed in a given period. By Johannes Bechberger Read: https://www.infoq.com/articles/open-source-java-profilers/

Как перезапускать упавшие тесты параллельно Тесты часто бывают нестабильными. Когда тест падает, его можно попробовать перезапустить несколько раз, но перезапуски могут увеличивать время сборки в 2-3 раза. В этой статье мы расскажем, как нам удалось решить эту проблему, а также поделимся инструментом для параллельного перезапуска упавших тестов, который разработали наши инженеры. Читать: https://habr.com/ru/companies/wrike/articles/728826/?utm_campaign=728826

Сам себе экосистема: Как я адаптировал старый смартфон под современные реалии и написал клиенты нужных мне сервисов Время неумолимо бежит вперед: выходят новые гаджеты, постепенно заменяя старые, превращая их в тыкву или в лучшем случае, в «тапочек» для звонков. Сейчас смартфоны стали практически одинаковы во всем: дисплей на всю площадь передней панели, почти полное отсутствие аппаратных кнопок, беспроводная зарядка… Это всё, конечно, здорово, но ведь иногда так хочется взять в руки старый, но такой необычный в наше время QWERTY-смартфон и попытаться его использовать как основной, да и цены на них могут приятно удивить: БУ девайс можно купить за несколько сотен рублей (~5-10$). Одна проблема — клиенты приложений на версии Android 1.6-2.0 безбожно устарели и давно не работают. Но иногда желание воскресить старый девайс превыше потребительского качества и тут я пришёл к мысли… а почему бы не написать с нуля свои клиенты популярных приложений? ВК с музыкой, YouTube, трекинг посылок. Так я и сел писать необходимые в повседневной жизни приложения, с нуля, на голом API Android, без каких либо фреймворков (и даже AppCompat). Получилось ли у меня это? Узнаем в статье! Читать: https://habr.com/ru/companies/timeweb/articles/726086/?utm_campaign=726086

Difference between Comparator and Comparable in Java - Interview Question Comparator and Comparable are two interfaces in Java API, which is used to compare two objects in Java. Though both are used for comparison there are some differences between them, a major difference between Comparable and Comparator is that the former is used to define the natural ordering of objects e.g. lexicographic order for java.lang.String, while later is used to define any alternative ordering for an object.  The main usage of java.lang.Comparable and java.util.Comparator interface is for sorting a list of objects in Java. Java Interview questions and tutorials Read: http://www.java67.com/2013/08/difference-between-comparator-and-comparable-in-java-interface-sorting.html