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.
XINS is a technology used to define, create, and invoke remote APIs. XINS is specification-oriented. When API specifications are written (in XML), XINS will transform them to HTML-based documentation and Java code for both the client-side and the server-side. The communication is based on HTTP. XINS competes with the complex SOAP technology. Main design goals include simplicity, scalability, and testability. XINS is not only a specification technology, but also an application development framework. It offers transaction logging, unique log documentation, and active code generation.
Restlet is a REST framework for Java. It supports all REST concepts (Resource, Representation, Connector, Component, etc.) and is suitable for both client and server Web applications. It supports major Web standards like HTTP, SMTP, XML, JSON, WADL, and Atom. Many extensions are also available to integrate with Servlet, Spring, Jetty, Grizzly, Simple, JAXB, JAX-RS, JiBX, Velocity, or FreeMarker. A GWT version is also available.
HTSQL a high-level query language and Web service gateway for relational databases. It comes with source code and is royalty free for any use with open source database systems such as MySQL, PostgreSQL, SQLite, etc. Licenses for using HTSQL in conjunction with proprietary databases such as Microsoft SQL and Oracle can be purchased.
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.