Download javax.ws.rs-api-2.0.jar and Learn How to Use It
How to Download and Use javax.ws.rs-api-2.0.jar in Java
If you are developing or consuming RESTful web services in Java, you might have come across the javax.ws.rs-api-2.0.jar file. This is a JAR file that contains the interfaces and annotations for JAX-RS 2.0, the Java API for RESTful Web Services. In this article, you will learn what this JAR file is, how to download it, and how to use it in your Java projects.
What is javax.ws.rs-api-2.0.jar?
The javax.ws.rs-api-2.0.jar file is a package file format that aggregates many Java class files and associated metadata and resources into one file. It is part of the JAX-RS 2.0 specification, which defines a standard way to create and consume RESTful web services in Java.
JAX-RS 2.0 is an annotation-driven Java API that aims to make development of web services built according to the Representational State Transfer (REST) architectural style in Java both straightforward and intuitive for you, the developer. It allows you to use annotations such as @Path, @GET, @POST, @Produces, @Consumes, etc., to define your web resources and map them to HTTP methods and media types.
Some of the features and benefits of JAX-RS 2.0 are:
It supports both server-side and client-side development.
It provides a standardized Client API that enables you to make HTTP requests to remote web services.
It supports various types of filters and interceptors that allow you to manipulate requests and responses.
It supports asynchronous processing of requests and responses.
It supports validation of input parameters using Bean Validation.
It supports hypermedia links and URI templates.
It supports various message body readers and writers that allow you to convert between Java objects and different media types, such as JSON, XML, HTML, etc.
How to Download javax.ws.rs-api-2.0.jar?
There are different ways to download the javax.ws.rs-api-2.0.jar file, depending on your preference and convenience. Here are some of them:
Using a browser
The simplest way to download the JAR file is to use a browser and navigate to a reliable source that hosts the file. For example, you can go to ( which is a popular repository for Maven artifacts, and search for "javax.ws.rs-api". You will see a list of versions available for this artifact. Click on the version 2.0 (or any other version you want) and you will see a page with more details about it. On this page, you will find a link to download the JAR file directly.
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<img src="(^i^)" alt="Screenshot of mvnrepository.com showing how to download javax.ws Using a URLConnection class
Another way to download the JAR file is to use the URLConnection class, which is a Java class that represents a connection between an application and a URL. The URLConnection class allows you to read and write data to and from the URL, as well as access various properties of the connection, such as the content type, the content length, the response code, etc.
To use the URLConnection class to download the JAR file, you need to follow these steps:
Create a URL object from the string representation of the JAR file URL, such as URL url = new URL("
Open a connection to the URL using the openConnection() method of the URL object, such as URLConnection connection = url.openConnection();
Get an input stream from the connection using the getInputStream() method of the URLConnection object, such as InputStream inputStream = connection.getInputStream();
Create an output stream to a local file where you want to save the JAR file, such as OutputStream outputStream = new FileOutputStream("javax.ws.rs-api-2.0.jar");
Read bytes from the input stream and write them to the output stream using a buffer, such as byte buffer = new byte; int bytesRead; while ((bytesRead = inputStream.read(buffer)) != -1) outputStream.write(buffer, 0, bytesRead);
Close both streams using the close() method, such as inputStream.close(); outputStream.close();
The following code snippet shows an example of using the URLConnection class to download the JAR file:
import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.URL; import java.net.URLConnection; public class DownloadJar public static void main(String args) throws Exception // Create a URL object from the JAR file URL URL url = new URL(" // Open a connection to the URL URLConnection connection = url.openConnection(); // Get an input stream from the connection InputStream inputStream = connection.getInputStream(); // Create an output stream to a local file OutputStream outputStream = new FileOutputStream("javax.ws.rs-api-2.0.jar"); // Read bytes from the input stream and write them to the output stream byte buffer = new byte; int bytesRead; while ((bytesRead = inputStream.read(buffer)) != -1) outputStream.write(buffer, 0, bytesRead); // Close both streams inputStream.close(); outputStream.close(); System.out.println("Downloaded successfully!");
How to Use javax.ws.rs-api-2.0.jar in Java?
Now that you have downloaded the JAR file, you might wonder how to use it in your Java projects. The JAR file contains the interfaces and annotations that define the JAX-RS 2.0 API, but it does not provide any implementation of those interfaces and annotations. Therefore, you need to use a JAX-RS 2.0 implementation library, such as Jersey or RESTEasy, along with the JAR file.
To use javax.ws.rs-api-2.0.jar in Java, you need to do the following:
Add both javax.ws.rs-api-2.0.jar and a JAX-RS 2.0 implementation library (such as jersey-bundle-2.x.jar or resteasy-jaxrs-3.x.jar) to your project's classpath.
Create a resource class that represents your web service endpoint. A resource class is a Java class that is annotated with @Path and contains methods that are annotated with @GET, @POST, @PUT, @DELETE, etc., to handle different HTTP requests.
Create an application class that extends javax.ws.rs.core.Application and overrides its getClasses() or getSingletons() method to return a set of resource classes or instances.
Deploy your application on a web container that supports servlet 3.x specification (such as Tomcat 7.x or higher) or on a Java EE application server (such as GlassFish 4.x or higher).
The following code snippet shows an example of creating a simple JAX-RS application using javax.ws.rs-api-2.0.jar and Jersey 2.x:
import javax.ws.rs.ApplicationPath; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.core.Application; import java.util.HashSet; import java.util.Set; // Define the application path @ApplicationPath("/api") public class MyApplication extends Application // Override the getClasses() method to return a set of resource classes @Override public Set> getClasses() Set> classes = new HashSet(); classes.add(MyResource.class); return classes; // Define the resource path @Path("/hello") public class MyResource // Define the HTTP method and the media type to produce @GET @Produces("text/plain") public String sayHello() return "Hello, world!";
To test your application, you can use a web browser or a HTTP client tool (such as Postman or curl) to send a GET request to the URL You should see the response "Hello, world!" in plain text.
How to configure the JAX-RS client and server components?
One of the advantages of using JAX-RS 2.0 is that it provides a standardized Client API that enables you to make HTTP requests to remote web services. The Client API is based on a fluent builder pattern that allows you to chain methods to create and configure a client instance, a web target instance, and a request invocation instance.
To use the Client API, you need to do the following:
Create a client instance using the static factory method ClientBuilder.newClient().
Create a web target instance from the client instance using the target() method and passing the base URI of the web service.
Create a request invocation instance from the web target instance using the request() method and optionally passing the media type(s) to accept.
Invoke the request using one of the HTTP methods, such as get(), post(), put(), delete(), etc., and passing an optional entity to send.
Process the response using the methods of the Response class, such as getStatus(), getHeaders(), readEntity(), etc.
The following code sn