CRest (Client REST) is a lightweight library that simplifies the integration of third party RESTful services into Java applications. CRest is mainly annotation-driven, allowing the developer to focus on the essential aspects of the integration of a REST service, such as the definition of the Java interface that maps the remote REST methods and the data model the interface will deal with. The rest is achieved by annotating a plain Java interface with the relevant information such as the service end-point, the desired timeouts, URL formats, etc. CRest will handle everything else, including HTTP request generation, auto marshalling of the response, and more.
Aletheia is a browser-like application for sending raw HTTP requests. It is designed for debugging and finding security issues in Web applications. It is possible to apply filters on every request and response which can modify the content, for making Basic Authentication or OAuth requests, for example. Because it is possible to modify every bit of the request, it is easy to exploit Web applications. That means you can set, for example, custom Cookies or User-Agents, or send file uploads to the server. It uses the Apache HTTP core components library to send HTTP requests. This application also helps you understand how the HTTP protocol works.