Java Weekly, Issue 185
Last updated: August 10, 2021
Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.
Get started with mocking and improve your application tests using our Mockito guide:
Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.
Get started with understanding multi-threaded applications with our Java Concurrency guide:
Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:
Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.
But these can also be overused and fall into some common pitfalls.
To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:
Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:
Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.
I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.
You can explore the course here:
Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.
Get started with Spring Data JPA through the guided reference course:
Refactor Java code safely — and automatically — with OpenRewrite.
Refactoring big codebases by hand is slow, risky, and easy to put off. That’s where OpenRewrite comes in. The open-source framework for large-scale, automated code transformations helps teams modernize safely and consistently.
Each month, the creators and maintainers of OpenRewrite at Moderne run live, hands-on training sessions — one for newcomers and one for experienced users. You’ll see how recipes work, how to apply them across projects, and how to modernize code with confidence.
Join the next session, bring your questions, and learn how to automate the kind of work that usually eats your sprint time.
Distributed systems often come with complex challenges such as service-to-service communication, state management, asynchronous messaging, security, and more.
Dapr (Distributed Application Runtime) provides a set of APIs and building blocks to address these challenges, abstracting away infrastructure so we can focus on business logic.
In this tutorial, we'll focus on Dapr's pub/sub API for message brokering. Using its Spring Boot integration, we'll simplify the creation of a loosely coupled, portable, and easily testable pub/sub messaging system:
Lots of interesting writeups on Java 9 this week.
Here we go…
1. Spring and Java
>> Introducing Spring Cloud Function [spring.io]
Spring has always adopted POJO-based approaches, now it’s time to focus on functional approaches. Spring Cloud is getting enhanced with a possibility of defining beans from function implementations – everything well integrated with Reactor.
>> How much projections can help? [blog.arnoldgalovics.com]
Using projection instead of entity-based fetching can significantly improve overall performance – which is not a surprise.
>> From Microservices to Service Blocks using Spring Cloud Function and AWS Lambda [kennybastani.com]
A practical look at Service Blocks using Spring Cloud Function and AWS Lambda. If you’re interested in seeing Spring Cloud Function in action – definitely have a look.
>> Scala vs Kotlin: Multiple Inheritance and the Diamond problem [blog.frankel.ch]
Scala and Kotlin have their own solutions to problems caused by multiple inheritance – worth having a look.
>> Mocking HTTP, Mockito style [specto.io]
When working with microservices, we often need to mock/stub HTTP endpoints – Hoverfly is one of the better tools for doing that.
>> Support for Java 9 in IntelliJ IDEA 2017.2 [jetbrains.com]
Java 9 will be (hopefully) released soon and IDE providers are coming up with new features for their tools – this time, we can have a look at new support in Intellij IDEA.
>> 5 Things You Need to Know When Using Hibernate with Mysql [thoughts-on-java.org]
Hibernate already supports most of the MySql’s features, but there are still a few things to remember that are not entirely abstracted away.
Also worth reading:
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>> Assuring Architectural Rules with ArchUnit [hascode.com]
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>> Basic Spring web application in Java, Kotlin and Scala – comparison [rskupnik.github.io]
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>> Java Command-Line Interfaces (Part 6): JOpt Simple [marxsoftware.blogspot.com]
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>> 5 Step Recipe: Everything You Need to Know for Staying Up-to-Date in Java [blog.takipi.com]
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>> Java Command-Line Interfaces (Part 7): JCommander [marxsoftware.blogspot.com]
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>> Java Annotated Monthly – July 2017 [jetbrains.com]
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>> Pragmatic Functional Programming [cleancoder.com]
Webinars and presentations:
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>> Git Questions – How and When do I Merge or Rebase? [jetbrains.com]
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>> Java Performance Engineer’s Survival Guide [infoq.com]
Time to upgrade:
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>> Spring Tool Suite 3.9.0 released [spring.io]
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>> Spring for Apache Hadoop 2.5.0 GA released [spring.io]
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>> Bean Validation 2.0 CR 2 released [beanvalidation.org]
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>> Spring Cloud Finchley M1 is available. [spring.io]
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>> Hibernate Validator 6.0.0.CR3 is out with Bean Validation 2.0.0.CR3 support [in.relation.to]
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>> Mockito 2.8.53 is out [github.com]
2. Technical
>> Project Package Organization [dolszewski.com]
Package structure in Java projects is often neglected or applied mindlessly – here we can see a comparison of the two most popular approaches: package-by-layer vs. package-by-feature.
>> Converting Queries to Commands [michaelfeathers.silvrback.com]
Raising the abstraction level and passing commands to objects can result in better decoupling – and Java 8 Lambda Expressions make it much easier and concise.
Also worth reading:
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>> Fine tuning embedded jetty inside of spark framework. [blog.codecentric.de]
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>> Gatling Load Testing Part 2 – Extending Gatling [blog.codecentric.de]
3. Musings
>> How to Write Test Cases [daedtech.com]
There is no universal answer to this problem – pick one of the scientific methods, follow it, and use the best tools possible.
>> Why Expert Developers Still Make Mistakes [daedtech.com]
We should make mistakes – those expose lacks in our knowledge that we can eventually fix.
Also worth reading:
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>> The Paradox of Apple Watch [bitquabit.com]
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>> Is There a Single Method for the Internet of Things? [queue.acm.org]
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>> Eric Han, VP at Portworx, Speaks to InfoQ on the State of the Hyperconverged Container Market [infoq.com]
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>> Why I Hate Slack and You Should Too [bitquabit.com]
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>> On crossing the bridge into unit testing land [ontestautomation.com]
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>> Maintenance hell? No, thanks! [blog.codecentric.de]
4. Comics
And my favorite Dilberts of the week:
