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JUnit 5 and Selenium – Using Selenium built-in `PageFactory` to implement Page Object Pattern

Selenium is a set of tools and libraries supporting browser automation and it is mainly used for web applications testing. One of the Selenium’s components is a Selenium WebDriver that provides client library, the JSON wire protocol (protocol to communicate with the browser drivers) and browser drivers. One of the main advantages of Selenium WebDriver is that it supported by ...

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Kotlin Data Classes: Why, What and How?

In this post on Kotlin’s data classes, we’ll take a look at how data classes are better than regular Java POJO (Plain Old Java Object) classes, and how they make our everyday lives easier. We’ll also take a look at some of the caveats of data classes. I’ve also written an article on Java vs Kotlin, if you’re interested, check ...

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How to fix an illegal start of expression in Java

Have you ever come across this mind-boggling bug and wonder how to solve it? Let’s go through the post and study how we address the Illegal start of expression Java error. This is a dynamic error, which means that the compiler finds something that doesn’t follow the rules or syntax of Java programming. Beginners mostly face this bug in Java. ...

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Efficient enterprise testing — conclusion (6/6)

java-interview-questions-answers

This last part of the series will cover additional end-to-end tests, testing in production, and a conclusion of the parts. Further end-to-end tests & testing in production Besides system tests that only verify a single application-under-test and mock external concerns, our pipeline must also include full end-to-end test that verify the system as a whole. The good news is that ...

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Become a Master of Java Streams – Part 1: Creating Streams

Declarative code (e.g. functional composition with Streams) provides superior code metrics in many cases. Code your way through this hands-on-lab article series and mature into a better Java programmer by becoming a Master of Java Streams. The whole idea with Streams is to represent a pipeline through which data will flow and the pipeline’s functions operate on the data. This ...

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JEP 355 Text Blocks in JDK 13

JDK 13 went GA on September 17th, 2019 and the prominent new features are listed here. One of the new features is “text blocks”. This allows writing multiline strings easily without the need for concatenation while splitting into different lines. Lets quickly look at the different ways of creating multiline strings: String aBlock = """ SELECT id, first_name, last_name, dob FROM ...

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Concurrent query execution in Apache Lucene

Apache Lucene is a wonderfully concurrent pure Java search engine, easily able to saturate the available CPU or IO resources on your server, if you ask it to. The concurrency model for a “typical” Lucene application is one thread per query at search time, but did you know Lucene can also execute a single query concurrently using multiple threads to ...

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Spring @Primary Annotation

spring-interview-questions-answers

Introduction: Spring @Primary annotation is used to give a higher preference to the marked bean when multiple beans of the same type exist. Spring, by default, auto-wires by type. And so, when Spring attempts to autowire and there are multiple beans of the same type, we’ll get a NoUniqueBeanDefinitionException: Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException   : No qualifying bean of type [com.programmergirl.Person]   is ...

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Recommendation System Using Spark ML Akka and Cassandra

Building a recommendation system with Spark is a simple task. Spark’s machine learning library already does all the hard work for us. In this study I will show you how to build a scalable application for Big Data using the following technologies: Scala LanguageSpark with Machine LearningAkka with ActorsCassandra A recommendation system is an information filtering mechanism that attempts to ...

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