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

Partner – Microsoft – NPI EA (cat = Baeldung)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Microsoft – NPI EA (cat= Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, you can get started over on the documentation page.

And, you can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat=Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

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Partner – Orkes – NPI EA (tag=Microservices)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

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eBook – Guide Spring Cloud – NPI EA (cat=Spring Cloud)
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eBook – Mockito – NPI EA (tag = Mockito)
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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.

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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eBook – Java Streams – NPI EA (cat=Java Streams)
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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:

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eBook – Jackson – NPI EA (cat=Jackson)
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Do JSON right with Jackson

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Course – LS – NPI EA (cat=Jackson)
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Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:

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Course – LSS – NPI EA (cat=Spring Security)
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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 – All Access – NPI EA (cat= Spring)
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All Access is finally out, with all of my Spring courses. Learn JUnit is out as well, and Learn Maven is coming fast. And, of course, quite a bit more affordable. Finally.

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Course – LSD – NPI EA (tag=Spring Data JPA)
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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:

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Partner – LambdaTest – NPI EA (cat=Testing)
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End-to-end testing is a very useful method to make sure that your application works as intended. This highlights issues in the overall functionality of the software, that the unit and integration test stages may miss.

Playwright is an easy-to-use, but powerful tool that automates end-to-end testing, and supports all modern browsers and platforms.

When coupled with LambdaTest (an AI-powered cloud-based test execution platform) it can be further scaled to run the Playwright scripts in parallel across 3000+ browser and device combinations:

>> Automated End-to-End Testing With Playwright

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eBook – Guide Spring Cloud – NPI (cat=Cloud/Spring Cloud)
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1. Overview

In this tutorial, we’re going to describe Spring Cloud OpenFeign — a declarative REST client for Spring Boot apps.

Feign makes writing web service clients easier with pluggable annotation support, which includes Feign annotations and JAX-RS annotations.

Also, Spring Cloud adds support for Spring MVC annotations and for using the same HttpMessageConverters as used in Spring Web.

One great thing about using Feign is that we don’t have to write any code for calling the service, other than an interface definition.

Further reading:

Retrying Feign Calls

Learn how to retry REST API calls with Feign library.

Feign Client Exception Handling

We'll demonstrate how to handle exceptions in Feign in a Spring Boot project.

Integration Tests With Spring Cloud Netflix and Feign

Let's explore how we can do integration testing of a Feign Client.

2. Dependencies

First, we’ll start by creating a Spring Boot web project and adding the spring-cloud-starter-openfeign dependency to our pom.xml file:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

Also, we’ll need to add the spring-cloud-dependencies:

 <dependencyManagement>
     <dependencies>
         <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

We can find the latest versions of spring-cloud-starter-openfeign and spring-cloud-dependencies on Maven Central.

3. Feign Client

Next, we need to add @EnableFeignClients to our main class:

@SpringBootApplication
@EnableFeignClients
public class ExampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(ExampleApplication.class, args);
    }
}

With this annotation, we enable component scanning for interfaces that declare they are Feign clients.

Then we declare a Feign client using the @FeignClient annotation:

@FeignClient(value = "jplaceholder", url = "https://jsonplaceholder.typicode.com/")
public interface JSONPlaceHolderClient {

    @RequestMapping(method = RequestMethod.GET, value = "/posts")
    List<Post> getPosts();

    @RequestMapping(method = RequestMethod.GET, value = "/posts/{postId}", produces = "application/json")
    Post getPostById(@PathVariable("postId") Long postId);
}

In this example, we’ve configured a client to read from the JSONPlaceholder APIs.

The value argument passed in the @FeignClient annotation is a mandatory, arbitrary client name, while with the url argument, we specify the API base URL.

Furthermore, since this interface is a Feign client, we can use the Spring Web annotations to declare the APIs that we want to reach out to.

4. Configuration

Now, it’s very important to understand that each Feign client is composed of a set of customizable components.

Spring Cloud creates a new default set on demand for each named client using the FeignClientsConfiguration class that we can customize as explained in the next section.

The above class contains these beans:

  • Decoder – ResponseEntityDecoder, which wraps SpringDecoder, used to decode the Response
  • Encoder – SpringEncoder is used to encode the RequestBody.
  • Logger – Slf4jLogger is the default logger used by Feign.
  • Contract – SpringMvcContract, which provides annotation processing
  • Feign-Builder – HystrixFeign.Builder is used to construct the components.
  • Client – LoadBalancerFeignClient or default Feign client

4.1. Custom Beans Configuration

If we want to customize one or more of these beans, we can override them by creating a Configuration class, which we then add to the FeignClient annotation:

@FeignClient(value = "jplaceholder",
  url = "https://jsonplaceholder.typicode.com/",
  configuration = ClientConfiguration.class)
public class ClientConfiguration {

    @Bean
    public OkHttpClient client() {
        return new OkHttpClient();
    }
}

In this example, we tell Feign to use OkHttpClient instead of the default one to support HTTP/2.

Feign supports multiple clients for different use cases, including the ApacheHttpClient, which sends more headers with the request, for example, Content-Length, which some servers expect.

To use these clients, let’s not forget to add the required dependencies to our pom.xml file:

<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-okhttp</artifactId>
</dependency>

<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-httpclient</artifactId>
</dependency>

We can find the latest versions of feign-okhttp and feign-httpclient on Maven Central.

4.2. Configuration Using Properties

Rather than use a Configuration class, we can use application properties to configure Feign clients, as shown in this application.yaml example:

feign:
  client:
    config:
      default:
        connectTimeout: 5000
        readTimeout: 5000
        loggerLevel: basic

With this configuration, we’re setting the timeouts to five seconds and the logger level to basic for each declared client in the application.

Finally, we can create the configuration with default as the client name to configure all @FeignClient objects, or we can declare the feign client name for a configuration:

feign:
  client:
    config:
      jplaceholder:

If we have both Configuration bean and configuration properties, configuration properties will override Configuration bean values.

5. Interceptors

Adding interceptors is another useful feature provided by Feign.

The interceptors can perform a variety of implicit tasks, from authentication to logging, for every HTTP request/response.

In this section, we’ll implement our own interceptor, as well as use the one provided by the Spring Cloud OpenFeign out-of-the-box. Both will add a basic authentication header to each request.

5.1. Implementing RequestInterceptor

Let’s implement our custom request interceptor:

@Bean
public RequestInterceptor requestInterceptor() {
  return requestTemplate -> {
      requestTemplate.header("user", username);
      requestTemplate.header("password", password);
      requestTemplate.header("Accept", ContentType.APPLICATION_JSON.getMimeType());
  };
}

Also, to add the interceptor to the request chain, we just need to add this bean to our Configuration class or, as we saw previously, declare it in the properties file:

feign:
  client:
    config:
      default:
        requestInterceptors:
          com.baeldung.cloud.openfeign.JSONPlaceHolderInterceptor

5.2. Using BasicAuthRequestInterceptor

Alternatively, we can use the BasicAuthRequestInterceptor class that the Spring Cloud OpenFeign provides:

@Bean
public BasicAuthRequestInterceptor basicAuthRequestInterceptor() {
    return new BasicAuthRequestInterceptor("username", "password");
}

It’s simple as that. Now all the requests will contain the basic authentication header.

6. Hystrix Support

Feign supports Hystrix, so if we have enabled it, we can implement the fallback pattern.

With the fallback pattern, when a remote service call fails, rather than generating an exception, the service consumer will execute an alternative code path to try to carry out the action through another means.

To achieve the goal, we need to enable Hystrix by adding feign.hystrix.enabled=true in the properties file.

This allows us to implement fallback methods that are called when the service fails:

@Component
public class JSONPlaceHolderFallback implements JSONPlaceHolderClient {

    @Override
    public List<Post> getPosts() {
        return Collections.emptyList();
    }

    @Override
    public Post getPostById(Long postId) {
        return null;
    }
}

To let Feign know that fallback methods have been provided, we also need to set our fallback class in the @FeignClient annotation:

@FeignClient(value = "jplaceholder",
  url = "https://jsonplaceholder.typicode.com/",
  fallback = JSONPlaceHolderFallback.class)
public interface JSONPlaceHolderClient {
    // APIs
}

7. Logging

For each Feign client, a logger is created by default.

To enable logging, we should declare it in the application.properties file using the package name of the client interfaces:

logging.level.com.baeldung.cloud.openfeign.client: DEBUG

Or, if we want to enable logging only for one particular client in a package, we can use the full class name:

logging.level.com.baeldung.cloud.openfeign.client.JSONPlaceHolderClient: DEBUG

Note that Feign logging responds only to the DEBUG level.

The Logger.Level that we may configure per client indicates how much to log:

public class ClientConfiguration {
    
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.BASIC;
    }
}

There are four logging levels to choose from:

  • NONE – no logging, which is the default
  • BASIC – log only the request method, URL and response status
  • HEADERS – log the basic information together with request and response headers
  • FULL – log the body, headers and metadata for both request and response

8. Error Handling

Feign’s default error handler, ErrorDecoder.default, always throws a FeignException.

Now, this behavior isn’t always the most useful. So, to customize the Exception thrown, we can use a CustomErrorDecoder:

public class CustomErrorDecoder implements ErrorDecoder {
    @Override
    public Exception decode(String methodKey, Response response) {

        switch (response.status()){
            case 400:
                return new BadRequestException();
            case 404:
                return new NotFoundException();
            default:
                return new Exception("Generic error");
        }
    }
}

Then, as we’ve done previously, we have to replace the default ErrorDecoder by adding a bean to the Configuration class:

public class ClientConfiguration {

    @Bean
    public ErrorDecoder errorDecoder() {
        return new CustomErrorDecoder();
    }
}

9. Conclusion

In this article, we discussed Spring Cloud OpenFeign and its implementation in a simple sample application.

We’ve also seen how to configure a client, add interceptors to our requests and handle errors using Hystrix and ErrorDecoder.

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)
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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.

Partner – Microsoft – NPI EA (cat = Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat = Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

Partner – Orkes – NPI EA (tag = Microservices)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

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

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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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)
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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)
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Working on getting your persistence layer right with Spring?

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Course – LS – NPI EA (cat=REST)

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Course – Spring Sale 2025 – NPI EA (cat= Baeldung)
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Course – Spring Sale 2025 – NPI (All)
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Partner – Microsoft – NPI (cat=Spring)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

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eBook – eBook Guide Spring Cloud – NPI (cat=Cloud/Spring Cloud)