Pros of OkHttp

• Simpler API and easier to use for common HTTP operations
• Built-in support for modern features like HTTP/2 and WebSockets
• More actively maintained with frequent updates and improvements

Cons of OkHttp

• Less flexible for advanced customization compared to HttpComponents
• Smaller ecosystem and fewer third-party extensions
• Limited support for older Java versions (requires Java 8+)

Code Comparison

OkHttp:

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
    .url("https://api.example.com")
    .build();
Response response = client.newCall(request).execute();

HttpComponents:

CloseableHttpClient client = HttpClients.createDefault();
HttpGet request = new HttpGet("https://api.example.com");
CloseableHttpResponse response = client.execute(request);

Both libraries provide similar functionality for making HTTP requests, but OkHttp's API is generally more concise and easier to use. HttpComponents offers more granular control over the request and response process, which can be beneficial for complex use cases.

OkHttp is often preferred for modern Android development and projects that prioritize simplicity, while HttpComponents may be a better choice for enterprise applications or scenarios requiring extensive customization.

Pros of unirest-java

• Simpler API with more intuitive method chaining
• Built-in support for JSON, XML, and form-encoded data
• Automatic request/response object mapping

Cons of unirest-java

• Less flexible for advanced use cases
• Smaller community and fewer resources compared to HttpComponents
• Limited configuration options for connection pooling and threading

Code Comparison

unirest-java:

HttpResponse<JsonNode> response = Unirest.post("http://example.com/api")
  .header("accept", "application/json")
  .queryString("apiKey", "123")
  .field("parameter", "value")
  .asJson();

httpcomponents-client:

HttpClient client = HttpClients.createDefault();
HttpPost post = new HttpPost("http://example.com/api");
post.setHeader("accept", "application/json");
post.setEntity(new UrlEncodedFormEntity(Arrays.asList(
    new BasicNameValuePair("parameter", "value"))));
HttpResponse response = client.execute(post);

unirest-java offers a more concise and readable syntax for making HTTP requests, with built-in support for various data formats. However, httpcomponents-client provides more granular control over the request process and is better suited for complex scenarios. The choice between the two depends on the specific requirements of your project and the level of control you need over HTTP operations.

Pros of async-http-client

• Designed for asynchronous, non-blocking operations
• Supports WebSocket connections out of the box
• Offers a more modern API with functional programming concepts

Cons of async-http-client

• Less mature and potentially less stable than httpcomponents-client
• Smaller community and fewer resources available
• May have a steeper learning curve for developers familiar with traditional blocking APIs

Code Comparison

async-http-client:

AsyncHttpClient client = Dsl.asyncHttpClient();
Future<Response> f = client.prepareGet("http://www.example.com/").execute();
Response r = f.get();

httpcomponents-client:

CloseableHttpClient client = HttpClients.createDefault();
HttpGet request = new HttpGet("http://www.example.com/");
HttpResponse response = client.execute(request);

Both libraries provide HTTP client functionality, but async-http-client focuses on asynchronous operations, while httpcomponents-client offers a more traditional blocking API. async-http-client is better suited for applications requiring high concurrency and non-blocking I/O, whereas httpcomponents-client may be more appropriate for simpler use cases or when working with legacy systems. The choice between the two depends on specific project requirements and the development team's familiarity with asynchronous programming concepts.

Pros of Vert.x

• Reactive and event-driven architecture, suitable for high-concurrency applications
• Polyglot support, allowing development in multiple programming languages
• Built-in clustering and high availability features

Cons of Vert.x

• Steeper learning curve due to its reactive programming model
• Less mature and smaller community compared to HttpComponents Client
• May be overkill for simple HTTP client needs

Code Comparison

Vert.x HTTP client example:

WebClient client = WebClient.create(vertx);
client.get(8080, "localhost", "/")
  .send(ar -> {
    if (ar.succeeded()) {
      System.out.println("Got response: " + ar.result().bodyAsString());
    } else {
      System.out.println("Error: " + ar.cause().getMessage());
    }
  });

HttpComponents Client example:

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet request = new HttpGet("http://localhost:8080/");
CloseableHttpResponse response = httpClient.execute(request);
System.out.println("Response: " + EntityUtils.toString(response.getEntity()));
httpClient.close();

Summary

Vert.x offers a more modern, reactive approach to HTTP client operations, making it suitable for high-concurrency scenarios. However, HttpComponents Client provides a simpler, more traditional API that may be easier to adopt for developers familiar with blocking I/O. The choice between the two depends on specific project requirements and the team's expertise.

Pros of google-http-java-client

• Seamless integration with Google APIs and services
• Built-in support for JSON and Protocol Buffers
• Automatic handling of OAuth 2.0 authentication

Cons of google-http-java-client

• Less flexible for non-Google API use cases
• Smaller community and fewer third-party extensions
• Steeper learning curve for developers unfamiliar with Google's ecosystem

Code Comparison

google-http-java-client:

HttpTransport httpTransport = new NetHttpTransport();
JsonFactory jsonFactory = new JacksonFactory();
HttpRequestFactory requestFactory = httpTransport.createRequestFactory();
HttpRequest request = requestFactory.buildGetRequest(new GenericUrl(url));
HttpResponse response = request.execute();

httpcomponents-client:

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet request = new HttpGet(url);
CloseableHttpResponse response = httpClient.execute(request);
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity);

Both libraries provide robust HTTP client functionality, but google-http-java-client is more tailored for Google API interactions, while httpcomponents-client offers a more general-purpose solution. The choice between them depends on the specific requirements of your project and whether you're primarily working with Google services or need a versatile HTTP client for various APIs.

Pros of Jetty

• Full-featured web server and servlet container, offering more comprehensive functionality
• Better suited for building and deploying web applications
• More active development and frequent updates

Cons of Jetty

• Larger footprint and potentially higher resource usage
• Steeper learning curve due to more complex architecture
• May be overkill for simple HTTP client needs

Code Comparison

Jetty (server setup):

Server server = new Server(8080);
ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
context.setContextPath("/");
server.setHandler(context);
server.start();

HttpComponents (client request):

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet request = new HttpGet("http://example.com");
CloseableHttpResponse response = httpClient.execute(request);
HttpEntity entity = response.getEntity();
String result = EntityUtils.toString(entity);

Summary

Jetty is a more comprehensive solution for web server and servlet container needs, while HttpComponents-Client focuses specifically on HTTP client functionality. Jetty offers a broader range of features but comes with increased complexity, while HttpComponents-Client provides a simpler, more focused approach to HTTP client operations. The choice between the two depends on the specific requirements of your project and the scope of functionality needed.