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 Java, the byte type is a signed 8-bit integer. This means it can hold values from -128 to 127. However, there are situations where we might need to work with bytes as if they were unsigned, representing values from 0 to 255. This can be especially important when dealing with binary data, networking, and file I/O where unsigned bytes are common.
In this tutorial, we’ll discover two approaches to converting an int to an unsigned byte in Java.
2. Using Type Casting and Bit Masking
The most common approach is to use type casting combined with bit masking. Let’s explore the implementation:
int value = 200;
@Test
public void givenInt_whenUsingTypeCastingAndBitMasking_thenConvertToUnsignedByte() {
byte unsignedByte = (byte) (value & 0xFF);
assertEquals(value, Byte.toUnsignedInt(unsignedByte));
}In this test, we begin by initializing an integer value of 200. Then, we employ the expression (value & 0xFF) to convert this integer into an unsigned byte representation. This operation involves a bitwise AND operation between the integer value and the hexadecimal value 0xFF, which corresponds to 255 in decimal or 11111111 in binary.
By executing this bitwise AND operation, we ensure that only the least significant 8 bits of the integer value are retained, effectively discarding any higher-order bits. Consequently, the resulting value of (value & 0xFF) represents an unsigned byte within the range of 0 to 255. Furthermore, this resultant unsigned byte value is then cast to a byte datatype using (byte), facilitating compatibility with Java’s byte type.
Subsequently, after obtaining this byte representation, we utilize the Byte.toUnsignedInt() method to correctly interpret it as an unsigned value.
3. Using ByteBuffer
Another approach involves using the ByteBuffer class to convert an int to a byte array and then extract the byte:
@Test
public void givenIntInRange_whenUsingByteBuffer_thenConvertToUnsignedByte() {
int value = 200;
ByteBuffer buffer = ByteBuffer.allocate(4).putInt(value);
byte unsignedByte = buffer.array()[3];
assertEquals(value, Byte.toUnsignedInt(unsignedByte));
}Here, we allocate a ByteBuffer of 4 bytes to store the integer value. Then, we utilize the putInt(value) method to store the integer in the buffer. Since the buffer stores the value in big-endian order by default, the least significant byte (which we need) is the fourth byte in the buffer (index 3).
4. Conclusion
In conclusion, while Java lacks an unsigned byte type, various techniques such as type casting combined with bit masking or using ByteBuffer provide effective means for converting an int to an unsigned byte, which is crucial for scenarios requiring the representation of values from 0 to 255.
