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Jareto - Java REST Tools


The following technologies already allow for convenient and efficient development of REST servers and clients:

However, these technologies currently lack certain features that are often required, forcing the developer to “re-invent the wheel” or fall back to lower-level technologies such as JSON-P in combination with

Jareto provides the following features in an easy-to-use way, for both server- and client-side development:

Depending on your requirements, you can use the server-side part of Jareto, or the client-side part, or both.


The Usage section below provides a crisp overview of how to apply Jareto’s features.

For a gentle introduction, read the Jareto article in Oracle’s Java Magazine.


To use the features provided by Jareto, add the following dependency to your project:

    <!-- for using server-side features -->

    <!-- for using client-side features -->

Since auto-discovery of providers may cause problems in complex applications, you have to explicitly return the Jareto provider classes from the getClasses method of your server-side Application class:


Likewise, if you want to use Jareto in a REST client, you have to register the Jareto provider classes during client construction:;

For a sample web application (including an in-container REST client and JUnit tests using a standalone REST client), see jareto-demo.

Transporting HTTP meta data

As a prerequisite, inject the following class to your server code:

private ServiceResponseBuilder _responseBuilder;

To set the HTTP status code on the server side:


To read the HTTP status code on the client side:


To add an HTTP header on the server side:

_responseBuilder.get().header(HEADER_NAME, HEADER_VALUE);

To add a static HTTP header on the server side (via class-level or method-level annotation to the REST interface):

@Header(name = HEADER_NAME, value = HEADER_VALUE)

To read an HTTP header on the client side:


To add an HTTP header to a client request:

ClientRequestHeaders.addHeader(HEADER_NAME, HEADER_VALUE);

Implementation note: The client-side part of Jareto uses Java ThreadLocals for managing data, which are also usable in standalone applications (as opposed to @RequestScoped). These ThreadLocals are cleared by the client-side Jareto filters.

Mapping Java Exceptions

The following exceptions are automatically mapped to and from HTTP wire data by Jareto:

To throw a checked exception on the server side:

throw new AppException(ERROR_CODE, ERROR_TEXT)

The error code and text will be transported as JSON payload. Extended constructors also allow transporting additional payload (by extending and explicitly setting the HTTP status code.

On the client side, the HTTP wire data is automatically transformed back into an AppException. The error code, text, and HTTP status are accessible via appropriate getters:


When transporting additional payload, the allowed entity classes must be registered explicitly as follows (to prevent Java deserialization attacks):


Certain aspects of the server-side mapping can be customized by defining and registering an IServiceExceptionCustomizer:

WebApplicationExceptionFactory.registerCustomizer(new IServiceExceptionCustomizer() {
  // override the methods that you want to customize here

Supported Runtimes

Jareto has been tested with the following Application Servers:

Release Notes

Version 1.1.5:

Version 1.1.4:

Version 1.1.3:

Version 1.1.2:

Version 1.1.1:

Version 1.1.0:

Version 1.0.0: