eBook – Guide Spring Cloud – NPI EA (cat=Spring Cloud)
announcement - icon

Let's get started with a Microservice Architecture with Spring Cloud:

>> Join Pro and download the eBook

eBook – Mockito – NPI EA (tag = Mockito)
announcement - icon

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:

Download the eBook

eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
announcement - icon

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:

>> Download the eBook

eBook – Reactive – NPI EA (cat=Reactive)
announcement - icon

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:

>> Join Pro and download the eBook

eBook – Java Streams – NPI EA (cat=Java Streams)
announcement - icon

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:

>> Join Pro and download the eBook

eBook – Jackson – NPI EA (cat=Jackson)
announcement - icon

Do JSON right with Jackson

Download the E-book

eBook – HTTP Client – NPI EA (cat=Http Client-Side)
announcement - icon

Get the most out of the Apache HTTP Client

Download the E-book

eBook – Maven – NPI EA (cat = Maven)
announcement - icon

Get Started with Apache Maven:

Download the E-book

eBook – Persistence – NPI EA (cat=Persistence)
announcement - icon

Working on getting your persistence layer right with Spring?

Explore the eBook

eBook – RwS – NPI EA (cat=Spring MVC)
announcement - icon

Building a REST API with Spring?

Download the E-book

Course – LS – NPI EA (cat=Jackson)
announcement - icon

Get started with Spring and Spring Boot, through the Learn Spring course:

>> LEARN SPRING
Course – RWSB – NPI EA (cat=REST)
announcement - icon

Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:

>> The New “REST With Spring Boot”

Course – LSS – NPI EA (cat=Spring Security)
announcement - icon

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:

>> Learn Spring Security

Course – LSD – NPI EA (tag=Spring Data JPA)
announcement - icon

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:

>> CHECK OUT THE COURSE

Partner – Moderne – NPI EA (cat=Spring Boot)
announcement - icon

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.

Course – LJB – NPI EA (cat = Core Java)
announcement - icon

Code your way through and build up a solid, practical foundation of Java:

>> Learn Java Basics

Partner – Diagrid – NPI EA (cat= Testing)
announcement - icon

In distributed systems, managing multi-step processes (e.g., validating a driver, calculating fares, notifying users) can be difficult. We need to manage state, scattered retry logic, and maintain context when services fail.

Dapr Workflows solves this via Durable Execution which includes automatic state persistence, replaying workflows after failures and built-in resilience through retries, timeouts and error handling.

In this tutorial, we'll see how to orchestrate a multi-step flow for a ride-hailing application by integrating Dapr Workflows and Spring Boot:

>> Dapr Workflows With PubSub

1. Overview

In this article, we’ll demonstrate the reason behind NoSuchFieldError and discover how to resolve it.

2. NoSuchFieldError

As the name suggests, NoSuchFieldError occurs when a specified field doesn’t exist. NoSuchFieldError extends the IncompatibleClassChangeError class and is thrown when the application tries to access or modify a field of an object or a static field of a class but the object or class no longer has that field.

IncompatibleClassChangeError class extends the LinkageError class and occurs when we perform incompatible class definition changes. Finally, LinkageError extends Error and shows that a class has some dependency on another incompatibly changed class.

Let’s see this error in action with the help of an example. As a first step, let’s create a Dependency class:

public class Dependency {
    public static String message = "Hello Baeldung!!";
}

Then we’ll create a FieldErrorExample class that refers to a field of our Dependency class:

public class FieldErrorExample {
    public static String getDependentMessage() {
        return Dependency.message;
    }
}

Let’s also add code to check whether we’re getting a message from the Dependency class:

public static void fetchAndPrint() {
    System.out.println(getDependentMessage());
}

Now, we can compile these files using the javac command, and upon execution of the FieldErrorExample class using the java command, it will print the specified message.

However, if we comment out, remove, or change the attribute name in the Dependency class and recompile it, then we’ll run into our error.

For example, let’s change the attribute name in our Dependency class:

public class Dependency {
    public static String msg = "Hello Baeldung!!";
}

Now, if we recompile only our Dependency class, and then execute FieldErrorExample again, we’ll encounter the NoSuchFieldError:

Exception in thread "main" java.lang.NoSuchFieldError: message

The above error occurred because the FieldErrorExample class still refers to the static field message of the Dependency class, but it no longer exists — we’ve made an incompatible change to the Dependency class.

3. Resolving the Error

To avoid this error, we need to clean and compile the existing files. We can do this using the javac command or with Maven by running mvn clean install. By performing this step, we’ll have all the latest compiled files, and we’ll avoid running into the error.

If the error persists, then the problem might be multiple JAR files: one while compiling, and another while running. This often happens when the application depends on external JARs. Here, we should validate the order of the JARs in the build path to identify the inconsistent JAR.

If we have to investigate further, it’s helpful to run the application with -verbose: class option to check the loaded classes. This can help us identify the outdated class.

Sometimes a third-party JAR might be internally referring to another version, which results in NoSuchFieldError. If this happens, we can use mvn dependency:tree -Dverbose. This generates the maven dependency tree and helps us in identifying the inconsistent JAR.

4. Conclusion

In this short tutorial, we have shown why NoSuchFieldError occurs and looked at how we can resolve it.

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.
Baeldung Pro – NPI EA (cat = Baeldung)
announcement - icon

Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:

>> Explore a clean Baeldung

Once the early-adopter seats are all used, the price will go up and stay at $33/year.

eBook – HTTP Client – NPI EA (cat=HTTP Client-Side)
announcement - icon

The Apache HTTP Client is a very robust library, suitable for both simple and advanced use cases when testing HTTP endpoints. Check out our guide covering basic request and response handling, as well as security, cookies, timeouts, and more:

>> Download the eBook

eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
announcement - icon

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:

>> Download the eBook

eBook – Java Streams – NPI EA (cat=Java Streams)
announcement - icon

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:

>> Join Pro and download the eBook

eBook – Persistence – NPI EA (cat=Persistence)
announcement - icon

Working on getting your persistence layer right with Spring?

Explore the eBook

Course – LS – NPI EA (cat=REST)

announcement - icon

Get started with Spring Boot and with core Spring, through the Learn Spring course:

>> CHECK OUT THE COURSE

Partner – Moderne – NPI EA (tag=Refactoring)
announcement - icon

Modern Java teams move fast — but codebases don’t always keep up. Frameworks change, dependencies drift, and tech debt builds until it starts to drag on delivery. OpenRewrite was built to fix that: an open-source refactoring engine that automates repetitive code changes while keeping developer intent intact.

The monthly training series, led by the creators and maintainers of OpenRewrite at Moderne, walks through real-world migrations and modernization patterns. Whether you’re new to recipes or ready to write your own, you’ll learn practical ways to refactor safely and at scale.

If you’ve ever wished refactoring felt as natural — and as fast — as writing code, this is a good place to start.

Course – LS – NPI (cat=Java)
announcement - icon

Get started with Spring Boot and with core Spring, through the Learn Spring course:

>> CHECK OUT THE COURSE

eBook Jackson – NPI EA – 3 (cat = Jackson)