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.
Corn Gate is designed to simplify service definitions and implementations in Java. It comes with several handy out-of-the-box functionalities, including security, registry, Spring and EJB integration, filters, shared data stages, client contexts, etc. JSON-RPC/HTTP and REST/HTTP protocols are supported. Remote service calls can be done through various client technologies. Since Gate supports standard HTTP communication mechanisms, almost any client technology can access services remotely.
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.
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.
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.
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.