DataNucleus AccessPlatform is a standards-compliant Java persistence product. It is fully compliant with the JDO1, JDO2, JDO2.1, JDO2.2, JDO3, JPA1, JPA2 and JPA2.1 Java standards, and provides a REST API. It complies with the OGC Simple Feature Spec for persistence of geospatial Java types. It allows access to all popular RDBMS available today, together with the MongoDB, LDAP, NeoDatis, JSON, Excel/ODF spreadsheets, XML, BigTable, HBase, and Neo4j databases.
VRaptor3 is a fully-fledged Java Web framework focused on fast development and maintainable code. It intends to make RESTful application development easy. A resource corresponds to a business logic annotated with its path and HTTP method. It runs inside DI Containers (Spring or Pico out of the box) and, therefore, enables full integration with them. Also, using Hibernate is easier: its session is automatically injected by VRaptor, so you just have to use it. VRaptor3 is refactor-friendly, especially in its redirecting configuration. It is also nicely extensible.
RestyGWT is a GWT generator for REST services and JSON encoded data transfer objects. RestyGWT Rest Services allow you to define an asynchronous service API which is then implemented via GWT deferred binding by RestyGWT. It features generation of asynchronous RESTful JSON based service proxies, encoding and decoding of Java objects to JSON, and an easy-to-use REST API.
Fulworx is a REST framework that uses simple annotations of XWork "Action" implementations to expose restful interfaces. Similar to Struts, Fulworx sits as a controller on top of Restlet. Each action is attached as a resource using Restlets. Standard resources are represented by default as XML (or JSON) using JAXB, but any representation may be specified. Actions may be used in other frameworks such as Struts and Webwork, since they're just XWork implementations.
SerfJ provides a very easy way of developing Java REST Web applications. It helps you to develop your application over an elegant MVC architecture, giving more importance to convention than configuration. This means, for example, you will not need configuration files or annotations in order to specify which view serves a controller's method. However, SerfJ is very flexible, so if you want to jump over those conventions, you can configure the behavior of your applications as you like. The framework tries to meet the JSR 311 specification, but it doesn't follow every point of the specification, because the purpose is to have a very intuitive library, and some some aspects of the specification are out of the scope of SerfJ.
WSF Staff is Web Service Framework for C++, AJAX, and J2ME that is based on Apache Axis2/C. WSF Staff wraps Apache Axis2/C code into C++, and also provides many additional features: a stateful Web services implementation in C++ with instance support, a synchronous and asynchronous client implementation in C++, AJAX, and J2ME, a service-component architecture implementation, support for RESTful Web services and clients, WSDL support with xsd import and export, J2ME client support (based on ksoap), a flexible and extensible code generator to generate any sort of Web service related source code (not only in C++), security support (users, groups, sessions, ACLs, etc.), and a Web application toolkit (webapp) with widget support.
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.