Retrieval-Augmented Generation (RAG) is a powerful approach in Artificial Intelligence that's very useful in a variety of tasks like Q&A systems, customer support, market research, personalized recommendations, and more.
A key component of RAG applications is the vector database , which helps manage and retrieve data based on semantic meaning and context.
Learn how to build a gen AI RAG application with Spring AI and the MongoDB vector database through a practical example:
Building a RAG App Using MongoDB and Spring AI
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 :
Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode , for a clean learning experience:
Once the early-adopter seats are all used, the price will go up and stay at $33/year.
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 .
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.
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 .
Whether you're just starting out or have years of experience, Spring Boot is obviously a great choice for building a web application.
Jmix builds on this highly powerful and mature Boot stack, allowing devs to build and deliver full-stack web applications without having to code the frontend. Quite flexibly as well, from simple web GUI CRUD applications to complex enterprise solutions.
Concretely, The Jmix Platform includes a framework built on top of Spring Boot, JPA, and Vaadin , and comes with Jmix Studio, an IntelliJ IDEA plugin equipped with a suite of developer productivity tools.
The platform comes with interconnected out-of-the-box add-ons for report generation, BPM, maps, instant web app generation from a DB, and quite a bit more:
Get non-trivial analysis (and trivial, too!) suggested right inside your IDE or Git platform so you can code smart, create more value, and stay confident when you push.
Get CodiumAI for free and become part of a community of over 280,000 developers who are already experiencing improved and quicker coding.
Write code that works the way you meant it to:
CodiumAI. Meaningful Code Tests for Busy Devs
The AI Assistant to boost Boost your productivity writing unit tests - Machinet AI .
AI is all the rage these days, but for very good reason. The
highly practical coding companion, you'll get the power of
AI-assisted coding and
automated unit test generation
.
Machinet's
Unit Test AI Agent
utilizes your own project
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with the behavior of the code.
And, the
AI Chat
crafts code and fixes errors with ease,
like a helpful sidekick.
Simplify Your Coding Journey with Machinet AI :
Install Machinet AI in your IntelliJ
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
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:
The New “REST With Spring Boot”
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:
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:
1. Overview
In this tutorial we’ll illustrate the most common use cases of the Apache
HttpAsyncClient
– from basic usage, to how to
set up a proxy
, how to use
SSL certificate
and finally – how to
authenticate
with the async client.
2. Simple Example
First – let’s see how to use HttpAsyncClient in a simple example – send a GET request:
@Test
void whenUseHttpAsyncClient_thenCorrect() throws InterruptedException, ExecutionException, IOException {
final SimpleHttpRequest request = SimpleRequestBuilder.get(HOST_WITH_COOKIE)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.build();
client.start();
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
Note how we need to start the async client before using it; without that, we would get the following exception:
java.lang.IllegalStateException: Request cannot be executed; I/O reactor status: INACTIVE
at o.a.h.u.Asserts.check(Asserts.java:46)
at o.a.h.i.n.c.CloseableHttpAsyncClientBase.
ensureRunning(CloseableHttpAsyncClientBase.java:90)
3. Multi-Threading With HttpAsyncClient
Now – let’s see how to use HttpAsyncClient to execute multiple requests simultaneously.
In the following example – we send three GET requests to three different host using HttpAsyncClient .
@Test
void whenUseMultipleHttpAsyncClient_thenCorrect() throws Exception {
final IOReactorConfig ioReactorConfig = IOReactorConfig
.custom()
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setIOReactorConfig(ioReactorConfig)
.build();
client.start();
final String[] toGet = { "http://www.google.com/", "http://www.apache.org/", "http://www.bing.com/" };
final GetThread[] threads = new GetThread[toGet.length];
for (int i = 0; i < threads.length; i++) {
final HttpGet request = new HttpGet(toGet[i]);
threads[i] = new GetThread(client, request);
for (final GetThread thread : threads) {
thread.start();
for (final GetThread thread : threads) {
thread.join();
Here is our GetThread implementation to handle the response:
static class GetThread extends Thread {
private final CloseableHttpAsyncClient client;
private final HttpContext context;
private final HttpGet request;
GetThread(final CloseableHttpAsyncClient client, final HttpGet request) {
this.client = client;
context = HttpClientContext.create();
this.request = request;
@Override
public void run() {
try {
final Future<HttpResponse> future = client.execute(request, context, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
} catch (final Exception ex) {
System.out.println(ex.getLocalizedMessage());
3.2. For HttpAsyncClient 4.5
@Test
void whenUseMultipleHttpAsyncClient_thenCorrect() throws Exception {
final ConnectingIOReactor ioReactor = new DefaultConnectingIOReactor();
final PoolingNHttpClientConnectionManager cm = new PoolingNHttpClientConnectionManager(ioReactor);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().setConnectionManager(cm).build();
client.start();
final String[] toGet = { "http://www.google.com/", "http://www.apache.org/", "http://www.bing.com/" };
final GetThread[] threads = new GetThread[toGet.length];
for (int i = 0; i < threads.length; i++) {
final HttpGet request = new HttpGet(toGet[i]);
threads[i] = new GetThread(client, request);
for (final GetThread thread : threads) {
thread.start();
for (final GetThread thread : threads) {
thread.join();
4. Proxy With HttpAsyncClient
Let’s see how to set up and use a proxy with the HttpAsyncClient.
In the following example – we send a HTTP GET request over proxy.
4.1. For HttpAsyncClient 5.x
@Test
void whenUseProxyWithHttpClient_thenCorrect() throws Exception {
final HttpHost proxy = new HttpHost("127.0.0.1", GetRequestMockServer.serverPort);
DefaultProxyRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxy);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setRoutePlanner(routePlanner)
.build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,HOST_WITH_PROXY);
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
4.2. For HttpAsyncClient 4.5
@Test
void whenUseProxyWithHttpClient_thenCorrect() throws Exception {
final CloseableHttpAsyncClient client = HttpAsyncClients.createDefault();
client.start();
final HttpHost proxy = new HttpHost("127.0.0.1", GetRequestMockServer.serverPort);
final RequestConfig config = RequestConfig.custom().setProxy(proxy).build();
final HttpGet request = new HttpGet(HOST_WITH_PROXY);
request.setConfig(config);
final Future<HttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
5. SSL Certificate With HttpAsyncClient
Now – let’s see how to use a SSL Certificate with HttpAsyncClient.
In the following example – we configure HttpAsyncClient to accept all certificates:
@Test
void whenUseSSLWithHttpAsyncClient_thenCorrect() throws Exception {
final TrustStrategy acceptingTrustStrategy = (certificate, authType) -> true;
final SSLContext sslContext = SSLContexts.custom()
.loadTrustMaterial(null, acceptingTrustStrategy)
.build();
final TlsStrategy tlsStrategy = ClientTlsStrategyBuilder.create()
.setHostnameVerifier(NoopHostnameVerifier.INSTANCE)
.setSslContext(sslContext)
.build();
final PoolingAsyncClientConnectionManager cm = PoolingAsyncClientConnectionManagerBuilder.create()
.setTlsStrategy(tlsStrategy)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setConnectionManager(cm)
.build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET",HOST_WITH_SSL);
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
5.2. For HttpAsyncClient 4.5
@Test
void whenUseSSLWithHttpAsyncClient_thenCorrect() throws Exception {
final TrustStrategy acceptingTrustStrategy = (certificate, authType) -> true;
final SSLContext sslContext = SSLContexts.custom()
.loadTrustMaterial(null, acceptingTrustStrategy)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setSSLHostnameVerifier(NoopHostnameVerifier.INSTANCE)
.setSSLContext(sslContext).build();
client.start();
final HttpGet request = new HttpGet(HOST_WITH_SSL);
final Future<HttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
6. Cookies With HttpAsyncClient
Next – let’s see how to use cookies with HttpAsyncClient.
In the following example – we set a cookie value before sending the request.
6.1. For HttpAsyncClient 5.x
@Test
void whenUseCookiesWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCookieStore cookieStore = new BasicCookieStore();
final BasicClientCookie cookie = new BasicClientCookie(COOKIE_NAME, "1234");
cookie.setDomain(COOKIE_DOMAIN);
cookie.setPath("/");
cookieStore.addCookie(cookie);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,HOST_WITH_COOKIE);
final HttpContext localContext = new BasicHttpContext();
localContext.setAttribute(HttpClientContext.COOKIE_STORE, cookieStore);
final Future<SimpleHttpResponse> future = client.execute(request, localContext, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
6.2. For HttpAsyncClient 4.5
@Test
void whenUseCookiesWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCookieStore cookieStore = new BasicCookieStore();
final BasicClientCookie cookie = new BasicClientCookie(COOKIE_NAME, "1234");
cookie.setDomain(COOKIE_DOMAIN);
cookie.setPath("/");
cookieStore.addCookie(cookie);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().build();
client.start();
final HttpGet request = new HttpGet(HOST_WITH_COOKIE);
final HttpContext localContext = new BasicHttpContext();
localContext.setAttribute(HttpClientContext.COOKIE_STORE, cookieStore);
final Future<HttpResponse> future = client.execute(request, localContext, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
7. Authentication With HttpAsyncClient
Next – let’s see how to use authentication with HttpAsyncClient.
In the following example – we use the CredentialsProvider to access a host through basic authentication.
7.1. For HttpAsyncClient 5.x
@Test
void whenUseAuthenticationWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();
final UsernamePasswordCredentials credentials =
new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS.toCharArray());
credsProvider.setCredentials(new AuthScope(URL_SECURED_BY_BASIC_AUTHENTICATION, 80) ,credentials);
final CloseableHttpAsyncClient client = HttpAsyncClients
.custom()
.setDefaultCredentialsProvider(credsProvider).build();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,URL_SECURED_BY_BASIC_AUTHENTICATION);
client.start();
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
7.2. For HttpAsyncClient 4.5
@Test
public void whenUseAuthenticationWithHttpAsyncClient_thenCorrect() throws Exception {
CredentialsProvider provider = new BasicCredentialsProvider();
UsernamePasswordCredentials creds = new UsernamePasswordCredentials("user", "pass");
provider.setCredentials(AuthScope.ANY, creds);
CloseableHttpAsyncClient client =
HttpAsyncClients.custom().setDefaultCredentialsProvider(provider).build();
client.start();
HttpGet request = new HttpGet("http://localhost:8080");
Future<HttpResponse> future = client.execute(request, null);
HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
8. Conclusion
In this article, we illustrated the various use cases of the asynchronous Apache Http client.
Baeldung Pro – NPI EA (cat = Baeldung)
Baeldung Pro comes with both absolutely No-Ads as well as
finally with Dark Mode, for a clean learning experience:
Once the early-adopter seats are all used, the price will go
up and stay at $33/year.
eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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:
Partner – Orkes – NPI EA (tag = Microservices)
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 – Microsoft – NPI EA (cat = Spring Boot)
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 – Jmix-Haulmont – NPI EA (cat= Spring Boot)
Whether you're just starting out or have years of experience,
Spring Boot is obviously a great choice for building a web
application.
Jmix builds on this highly powerful and mature Boot stack,
allowing devs to build and deliver full-stack web
applications without having to code the frontend. Quite
flexibly as well, from simple web GUI CRUD applications to complex
enterprise solutions.
Concretely, The Jmix Platform includes a framework built
on top of Spring Boot, JPA, and Vaadin, and comes with Jmix
Studio, an IntelliJ IDEA plugin equipped with a suite of
developer productivity tools.
The platform comes with interconnected out-of-the-box
add-ons for report generation, BPM, maps, instant web app
generation from a DB, and quite a bit more:
Partner – Machinet – NPI EA (cat = Baeldung)
The AI Assistant to boost Boost your productivity writing unit
tests - Machinet AI.
AI is all the rage these days, but for very good reason. The
highly practical coding companion, you'll get the power of
AI-assisted coding and automated unit test generation.
Machinet's Unit Test AI Agent utilizes your own project
context to create meaningful unit tests that intelligently aligns
with the behavior of the code.
And, the AI Chat crafts code and fixes errors with ease,
like a helpful sidekick.
Simplify Your Coding Journey with Machinet AI:
Install Machinet AI in your IntelliJ
Partner – Codium – NPI EA (cat = Testing)
Explore the secure, reliable, and high-performance Test
Execution Cloud built for scale. Right in your IDE:
CodiumAI. Meaningful Code Tests for Busy Devs
Basically, write code that works the way you meant it to.
Partner – Machinet – NPI EA (cat = Testing)
AI is all the rage these days, but for very good reason. The
highly practical coding companion, you'll get the power of
AI-assisted coding and automated unit test generation.
Machinet's Unit Test AI Agent utilizes your own project
context to create meaningful unit tests that intelligently aligns
with the behavior of the code.
Simplify Your Coding Journey with Machinet AI:
Install Machinet AI in your IntelliJ
eBook – Java Streams – NPI EA (cat=Java Streams)
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
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:
eBook – HTTP Client – NPI EA (cat=HTTP Client-Side)
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:
Course – LS – NPI EA (cat=REST)Course – LS – NPI (cat=HTTP Client-Side)
Get started with Spring Boot and with core Spring,
through the Learn Spring course:
the E-book
Course – RWSB – NPI EA (cat=REST)