Interoperable means an application's development platform or running platform shouldn't matter, but on this score, Ajax is headed for the same problems that have plagued Web services. That's the opinion of Marina Fisher, enterprise architect for Sun Microsystems, and Laurence Moroney, director of technology evangelism for Mainsoft, co-authors (with Ray Lai and Sonu Sharma) of the new book, Java EE and .Net Interoperability (Prentice Hall PTR, 2006).
Although Web services are supposed to be platform-agnostic, achieving interoperability (say from J2EE to .Net systems) is difficult. In particular, using vendor tools that generate Web services semantics in WSDL may produce message structures that are not cross-platform compatible. Similar problems can occur with the SOAP-encoded data model, weakly typed data objects and incompatible name spaces.
Most enterprise shops work in a mixed environment, and interoperability is usually not an option. Although the desire to jump on Web 2.0/Ajax technologies is great, vendors and developers must cooperate, and a level of standardization must be agreed upon to achieve interoperability. The process that leads to this standardization will not happen by accident; and the sooner it starts, the better. --Nelson King