Caucho To Support Java EE6 Web Profile in Resin 4.0
Caucho has announced their intent to support the Java EE6 Web Profile in Resin 4.0, their lightweight, next-generation application server. Resin's long enjoyed speed, especially in comparison to some of the bigger vendors' offerings, and the revised view underlying Java EE6's Profiles has allowed Resin to take the modular application server a step further.
Java EE6 Profiles are a mechanism that lets the specification describe groupings of technology that may not include all the functionality to merit full Java EE6 certification. The reasons for this are practical: full certification represents an implementation burden, and for a lot of people the full stack - with its backwards-compatibility and often use-case-specific APIs (like JCA, for example) - is neither required nor useful.
The Web Profile is one such grouping. The Web Profile specification includes support for many technologies: JSF 2, Facelets, JSP, and Servlets 3.0 on the web-tier. It also includes bean validation, JPA 2 for persistence, JTA for transaction management, and EJB 3.1 Lite for business-tier services, and CDI - which describes a general component model. EJB 3.1 Lite, as a specification, is a trimmed implementation of the EJB 3.1 specification. It is geared towards web application stacks, and so lacks support for features like JAXRS (REST endpoints), SOAP, RMI/CORBA, backwards compatibility with EJB 2.x, asynchronous services and message driven beans.
Implementors, however, are free to exceed these minimums. Resin does, exposing (for example) a remoting layer using Caucho's Hessian technology (not RMI, or SOAP), and providing a minimal, but very efficient JMS implementation along with support for message driven beans. The EJB 3.1 Lite container will also support asynchronous methods, scheduled methods and more.
I spoke with Reza Rahman - engineering lead on the EJB 3.1 Lite container for Caucho, as well as an expert group member for Java EE6 and EJB 3.1 - about the direction Caucho is taking with Resin. The goal, he explains, is to provide a lightweight application server and - wherever possible - go beyond the specifications. Caucho's eating their own dog-food, as it were, by basing the entire server on the CDI component model. Eventually, all services made available by the container will be surfaced on top of their implementation of CDI, called CanDI. Clients of these services won't be aware of the difference, but in the implementation, an EJB component will be no different than a regular CDI bean with EJB stereotypes applied. Indeed, the Resin EJB 3.1 Lite container allows the use of EJB service annotations outside EJBs. This architecture is a reflection of the general shift from distinct services to a unified component model underlining the Java EE6 specifications; "we see the legacy EJB component model as an evolutionary dead end at this point but there are better ways forward for business services defined in the EJB specification," says Rahman.
On whether Caucho would ultimately seek full Java EE6 certification for Resin, Rahman made it clear that they wouldn't, explaining that the older APIs aren't being used and that Caucho would keep Resin competitive and implement and innovate where required.
Rahman emphasized that Caucho's very interested in feedback from the community and encourages people to try the offering. Caucho also provides a PHP implementation called Quercus that has been generally well received. Besides Web Profile compliance, Caucho will work to move Resin to the cloud.
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