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. Overview
In this quick tutorial, we’ll learn about the Java XOR operator. We’ll discuss a bit of theory about XOR operations, and then we’ll see how to implement them in Java.
2. The XOR Operator
Let’s begin with a reminder of the semantics of the XOR operation. The XOR logical operation, exclusive or, takes two boolean operands and returns true if, and only if, the operands are different. Conversely, it returns false if the two operands have the same value.
So, for example, the XOR operator can be used when we have to check for two conditions that can’t be true at the same time.
Let’s consider two conditions, A and B. The following table shows the possible values of A XOR B:
The A XOR B operation is equivalent to (A AND !B) OR (!A AND B). Parentheses have been included for clarity, but are optional, as the AND operator takes precedence over the OR operator.
3. How to Do It in Java?
Now let’s see how to express the XOR operation in Java. Of course, we have the option to use the && and || operators, but this can be a bit wordy, as we’re going to see.
Imagine a Car class having two boolean attributes: diesel and manual. Now let’s say we want to tell if the car is either diesel or manual, but not both.
Let’s check this using the && and || operators:
Car car = Car.dieselAndManualCar();
boolean dieselXorManual = (car.isDiesel() && !car.isManual()) || (!car.isDiesel() && car.isManual());That’s a bit long, especially considering that we have an alternative, the Java XOR operator represented by the ^ symbol. It’s a bitwise operator, meaning it’s an operator comparing the matching bits of two values in order to return a result. In the XOR case, if two bits of the same position have the same value, the resulting bit will be 0. Otherwise, it’ll be 1.
So instead of our cumbersome XOR implementation, we can use the ^ operator directly:
Car car = Car.dieselAndManualCar();
boolean dieselXorManual = car.isDiesel() ^ car.isManual();As we can see, the ^ operator allows us to be more concise in expressing XOR operations.
Finally, it’s worth mentioning that the XOR operator, like the other bitwise operators, works with every primitive type. For example, let’s consider two integers, 1 and 3, whose binary representations are 00000001 and 000000011, respectively. Using the XOR operator between them will result in the integer 2:
assertThat(1 ^ 3).isEqualTo(2);Only the second bit is different in those two numbers; therefore, the result of the XOR operator on this bit will be 1. All other bits are identical, so their bitwise XOR result is 0, giving us a final value of 00000010, the binary representation of the integer 2.
4. Conclusion
In this article, we learned about the Java XOR operator. We demonstrated how it offers a concise way to express XOR operations.
