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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.

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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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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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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.

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

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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.

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Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.

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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.

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1. Overview

In this tutorial, we’ll examine two important HTTP methods, PUT and POST, that we frequently use within the REST architecture. It’s no secret that developers sometimes struggle to choose between these two methods while designing a RESTful web service. Therefore, we’ll address this issue with a simple implementation of a RESTful application in Spring Boot.

2. PUT vs POST Dilemma

In a typical REST architecture, a client sends requests in the form of HTTP methods to the server to create, retrieve, modify, or destroy resources. While we can use both PUT and POST to create resources, there are significant differences between them in terms of their intended applications.

According to the RFC 2616 standard, the POST method should be used to request that the server accept the enclosed entity as a subordinate of the existing resource identified by the Request-URI. This means the POST method call will create a child resource under a collection of resources.

Conversely, the PUT method should be used to request that the server store the enclosed entity under the provided Request-URI. If the Request-URI points to an existing resource on the server, the supplied entity will be considered a modified version of the existing resource. Therefore, the PUT method call will either create a new resource or update an existing one.

Another important difference between the methods is that PUT is an idempotent method, while POST isn’t. For instance, calling the PUT method multiple times will either create or update the same resource. In contrast, multiple POST requests will lead to the creation of the same resource multiple times.

3. Sample Application

To demonstrate the difference between PUT and POST, we’ll create a simple RESTful web application using Spring Boot. The application will store the names and addresses of people.

3.1. Maven Dependencies

To begin with, we need to include the dependencies for Spring Web, Spring Data JPA, and the in-memory H2 database in our pom.xml file:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>

3.2. Domain Entity and Repository Interface

Let’s start by creating the domain object first. For the address book, we’ll define an Entity class called Address that we’ll use to store the address information of individuals. For the sake of simplicity, we’ll use three fields, name, city, and postalCode, for our Address entity:

@Entity
public class Address {

    private @Id @GeneratedValue Long id;
    private String name;
    private String city;
    private String postalCode;

    // constructors, getters, and setters
}

The next step is to access the data from the database. For simplicity, we’ll leverage Spring Data JPA’s JpaRepository. This will allow us to perform CRUD functionalities on the data without writing any additional code:

public interface AddressRepository extends JpaRepository<Address, Long> {
}

3.3. REST Controller

Finally, we need to define the API endpoints for our application. We’ll create a RestController that will consume HTTP requests from the client and send back the appropriate response.

Here, we’ll define a @PostMapping for creating new addresses and storing them in the database, and a @PutMapping to update the content of the address book based on the request URI. If the URI isn’t found, it will create a new address and store it in the database:

@RestController
public class AddressController {

    private final AddressRepository repository;

    AddressController(AddressRepository repository) {
        this.repository = repository;
    }

    @PostMapping("/addresses")
    Address createNewAddress(@RequestBody Address newAddress) {
        return repository.save(newAddress);
    }

    @PutMapping("/addresses/{id}")
    Address replaceEmployee(@RequestBody Address newAddress, @PathVariable Long id) {

        return repository.findById(id)
            .map(address -> {
                address.setCity(newAddress.getCity());
                address.setPin(newAddress.getPostalCode());
                return repository.save(address);
            })
            .orElseGet(() -> {
                return repository.save(newAddress);
            });
    }
    //additional methods omitted
}

3.4. cURL Requests

Now we can test our developed application by using cURL to send sample HTTP requests to our server.

For creating a new address, we’ll enclose the data in JSON format and send it through a POST request:

curl -X POST --header 'Content-Type: application/json' \
    -d '{ "name": "John Doe", "city": "Berlin", "postalCode": "10585" }' \ 
    http://localhost:8080/addresses

Now let’s update the content of the address we created. We’ll send a PUT request using the id of that address in the URL. In this example, we’ll update the city and the postalCode section of the address we just created. We’ll suppose it was saved with id=1:

curl -X PUT --header 'Content-Type: application/json' \
  -d '{ "name": "John Doe", "city": "Frankfurt", "postalCode": "60306" }' \ 
  http://localhost:8080/addresses/1

4. Conclusion

In this article, we discussed the conceptual differences between the HTTP methods PUT and POST. Additionally, we learned how these methods can be implemented using the Spring Boot framework for developing RESTful applications.

In conclusion, we should use the POST method to create a new resource, and the PUT method to update an existing resource.

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:

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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 – 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 – LS – NPI (cat=REST)
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Get started with Spring Boot and with core Spring, through the Learn Spring course:

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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.

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