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:

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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.

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 – Guide Spring Cloud – NPI EA (cat=Spring Cloud)
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Let's get started with a Microservice Architecture with Spring Cloud:

>> Join Pro and download the eBook

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.

Get started with mocking and improve your application tests using our Mockito guide:

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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:

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eBook – Reactive – NPI EA (cat=Reactive)
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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:

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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:

>> Join Pro and download the eBook

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

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eBook – HTTP Client – NPI EA (cat=Http Client-Side)
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Get the most out of the Apache HTTP Client

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eBook – Maven – NPI EA (cat = Maven)
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Get Started with Apache Maven:

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

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eBook – RwS – NPI EA (cat=Spring MVC)
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Building a REST API with Spring?

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Course – LS – NPI EA (cat=Jackson)
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Get started with Spring and Spring Boot, through the Learn Spring course:

>> LEARN SPRING
Course – RWSB – NPI EA (cat=REST)
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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)
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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.

>> GET THE COURSE
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:

>> CHECK OUT THE COURSE

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

Course – Spring Sale 2025 – NPI EA (cat= Baeldung)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

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Course – Spring Sale 2025 – NPI (cat=Baeldung)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

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

In this article, we’re going to look at the new Spring Cloud Bus project. Spring Cloud Bus uses lightweight message broker to link distributed system nodes. The primary usage is to broadcast configuration changes or other management information. We can think about it as a distributed Actuator.

The project uses AMQP broker as the transport, but Apache Kafka or Redis can be utilized instead of RabbitMQ. Other transports are not supported yet.

Over the course of this tutorial, we’re going to use RabbitMQ as our main transport – which we’ll naturally have running already.

2. Prerequisites

Before we begin, it’s recommended to have already completed “Quick Intro to Spring Cloud Configuration“. We’re going to take an existing cloud config server and client to extend them and add automatic notifications about configuration changes.

2.1. RabbitMQ

Let’s start with RabbitMQ, which we recommend running as RabbitMQ as a docker image. This is quite simple to set up – to get RabbitMQ running locally, we need to install Docker and run following commands once Docker is installed successfully:

docker pull rabbitmq:3-management

This command pulls RabbitMQ docker image together with management plugin installed and enabled by default.

Next, we can run RabbitMQ:

docker run -d --hostname my-rabbit --name some-rabbit -p 15672:15672 -p 5672:5672 rabbitmq:3-management

Once we executed the command, we can go to the web browser and open http://localhost:15672, which will show the management console login form. The default username is: ‘guest’; password: ‘guest’. RabbitMQ will also listen on port 5672.

3. Adding Actuator to Cloud Config Client

We should have cloud config server and cloud config client both running. To refresh configuration changes a restart of the client is required every time – which is not ideal.

Let’s stop config client and annotate ConfigClient controller class with @RefreshScope:

@SpringBootApplication
@RestController
@RefreshScope
public class SpringCloudConfigClientApplication {
    // Code here...
}

Finally, let’s update the pom.xml file and add Actuator:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-actuator</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>

The latest version can be found here.

By default, all sensitive endpoints added by the actuator are secured. This includes ‘/refresh’ endpoint. For simplicity, we will turn off security by updating application.yml:

management:
  security:
    enabled: false

Additionally, starting with Spring Boot 2, actuator endpoints are not exposed by default. To make them available for access, we need to add this in an application.yml:

management:
  endpoints:
    web:
      exposure:
        include: "*"

Let’s start the client first and update user role from existing ‘Developer’ to ‘Programmer’ in the properties file on GitHub. Config server will show updated values straight away; however, the client won’t. To make client see new files we just need to send an empty POST request to ‘/refresh’ endpoint, which was added by actuator:

$> curl -X POST http://localhost:8080/actuator/refresh

We will get JSON file back showing updated properties:

[
  "user.role"
]

Finally, we can check if the user role was updated:

$> curl http://localhost:8080/whoami/Mr_Pink
Hello Mr_Pink! You are a(n) Programmer and your password is 'd3v3L'.

The user role was updated successfully and by calling ‘/refresh’ endpoint. Client updated configuration without restarting.

4. Spring Cloud Bus

By using Actuator, we can refresh clients. However, in the cloud environment, we would need to go to every single client and reload configuration by accessing actuator endpoint.

To solve this problem, we can use Spring Cloud Bus.

4.1. Client

We need to update cloud config client so that it can subscribe to RabbitMQ exchange:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
    <version>4.1.1</version>
</dependency>

The latest version can be found here.

To complete config client changes we need to add RabbitMQ details and enable cloud bus in an application.yml file:

---
spring:
  rabbitmq:
    host: localhost
    port: 5672
    username: guest
    password: guest
  cloud:
    bus:
      enabled: true
      refresh:
        enabled: true

Please note that we are using default username and password. This needs to be updated for real life, production applications. For this tutorial this is fine.

Now, the client will have another endpoint ‘/bus-refresh’. Calling this endpoint will cause:

  • get the latest configuration from the config server and update its configuration annotated by @RefreshScope
  • send a message to AMQP exchange informing about refresh event
  • all subscribed nodes will update their configuration as well

This way, we don’t need to go to individual nodes and trigger configuration update.

4.2. Server

Finally, let’s add two dependencies to config server to automate configuration changes fully.

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-config-monitor</artifactId>
    <version>4.1.1</version>
</dependency>

The latest version can be found here.

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
    <version>4.1.1</version>
</dependency>

The most recent version can be found here.

We will use spring-cloud-config-monitor to monitor configuration changes and broadcast events using RabbitMQ as transport.

We just need to update application.properties and give RabbitMQ details:

spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672
spring.rabbitmq.username=guest
spring.rabbitmq.password=guest

4.3. GitHub Webhook

Everything is set now. Once the server gets notified about configuration changes, it will broadcast this as a message to RabbitMQ. The client will listen to messages and update its configuration when configuration change event is transmitted. However, how a server will now about the modification?

We need to configure a GitHub Webhook. Let’s go to GitHub and open our repository holding configuration properties. Now, let’s select Settings and Webhook. Let’s click on Add webhook button.

Payload URL is the URL for our config server ‘/monitor’ endpoint. In our case the URL will be something like this:

http://root:s3cr3t@REMOTE_IP:8888/monitor

We just need to change Content type in the drop-down menu to application/json. Next, please leave Secret empty and click on Add webhook button – after that, we are all set.

5. Testing

Let’s make sure all applications are running. If we go back and check client it will show user.role as ‘Programmer’ and user.password as ‘d3v3L‘:

$> curl http://localhost:8080/whoami/Mr_Pink
Hello Mr_Pink! You are a(n) Programmer and your password is 'd3v3L'.

Previously, we had to use ‘/refresh’ endpoint to reload configuration changes. Let’s open properties file, change user.role back to Developer and push the changes:

user.role=Programmer

If we check the client now, we will see:

$> curl http://localhost:8080/whoami/Mr_Pink
Hello Mr_Pink! You are a(n) Developer and your password is 'd3v3L'.

Config client updated its configuration without restarting and without explicit refresh almost simultaneously. We can go back to GitHub and open the recently created Webhook. At the very bottom, there are Recent Deliveries. We can select one on the top of the list (assuming this was the first change – there will be only one anyway) and examine JSON that has been sent to config server.

We can also check config and server logs, and we will see entries:

o.s.cloud.bus.event.RefreshListener: Received remote refresh request. Keys refreshed []

6. Conclusion

In this article, we took existing spring cloud config server and client and added actuator endpoint to refresh client configuration. Next, we used Spring Cloud Bus to broadcast configuration changes and automate client updates. We also configured GitHub Webhook and tested the whole setup.

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)
announcement - icon

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)
announcement - icon

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:

>> Download the eBook

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?

Explore the eBook

Course – LS – NPI EA (cat=REST)

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

>> CHECK OUT THE COURSE

Course – Spring Sale 2025 – NPI EA (cat= Baeldung)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

>> EXPLORE ACCESS NOW

Course – Spring Sale 2025 – NPI (All)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

>> EXPLORE ACCESS NOW

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.

eBook Jackson – NPI EA – 3 (cat = Jackson)
eBook – eBook Guide Spring Cloud – NPI (cat=Cloud/Spring Cloud)