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:
1. Introduction
In this quick tutorial, we’ll learn how to find JAVA_HOME on Windows, Mac, and Linux.
As we all know, JAVA_HOME is an environment variable that we commonly use to locate java executables, like java and javac.
2. Windows-Specific Ways to Find JAVA_HOME
If we’re using Windows as the operating system, first we need to open up our command line (cmd) and type:
echo %JAVA_HOME%If JAVA_HOME is defined in our environment, then the above command will print it out.
Or to show the location of the java executable, we can try:
where java3. macOS and Linux-Specific Ways to Find JAVA_HOME
If we’re using either macOS or Linux, we can open up our terminal and type:
echo $JAVA_HOMEIf JAVA_HOME is defined in our environment, then the above command will print it out.
Or we could try:
which javaThis probably just shows us /usr/bin/java, which really isn’t very helpful since it’s a symbolic link. To unravel this, we’ll use dirname and readlink.
For Linux:
dirname $(dirname $(readlink -f $(which javac)))For macOS:
$(dirname $(readlink $(which javac)))/java_homeThis command prints the currently used java folder.
4. Using Java to Find JAVA_HOME
If we’re able to run java ourselves, then we have a nearly platform-independent way as well:
java -XshowSettings:properties -versionRunning this command outputs numerous properties, one of them being java.home.
To parse it though, we’ll still need a platform-specific tool.
For Linux and macOS, we’ll use grep:
java -XshowSettings:properties -version 2>&1 > /dev/null | grep 'java.home'
For Windows, we’ll use findstr:
java -XshowSettings:properties -version 2>&1 | findstr "java.home"5. Conclusion
In this brief article, we learned how to find JAVA_HOME on different operating systems.
If this didn’t work though, it’s possible we didn’t set the JAVA_HOME variable properly while installing Java.
