Sun has said XML and Web services will be a big focus of Mustang. Thus, regarding enterprise client and XML enhancements for Mustang, Sun will feature JAX-WS (Java Architecture for XML-Web Services) 2.0—which was formerly known as JAX-RPC—and JAXB (Java Architecture for XML Binding) 2.0. Mustang also will feature JDBC (Java Database Connectivity) 4.0.
However, despite all the planned improvements, the JDK team warns that not all of them will make it into Mustang. That is why Sun is asking developers to try the latest "snapshots" of Mustang that are being made available, so they can report and help fix bugs. Sun drops a new build of Mustang every week.
"I think Java 5 [JDK 1.5] had major changes, including language changes [annotations, new for-loop, auto-boxing, static imports, etc.] but so far the Java 6 items are a bit underwhelming in terms of their universal applicability," said Cameron Purdy, president of Tangosol Inc., of Somerville, Mass.
Bob Laferriere, vice president of engineering at Echelon 4 Corp., of Mequon, Wis., said, "The biggest improvements are all the Web services and XML-related enhancements. JAXB 2 will add schema support. The binding from the schema to Java classes is huge for me as it will create a seamless transition from structured XML documents to Java classes. This will enable systems and software engineering to have a simpler handoff. As with most JSRs, however, my fear is that there will again be an attempt to reinvent the wheel."
Laferriere questioned the need to include so much in the core.
"On the negative side, how much of these new features are really needed as part of the core JDK?" he asked. "As Java 6 increases its footprint, the large, slow tag will begin to creep back in with Java. This is also true of .Net, which is also growing quite large. It is almost a battle for the entire platform at this point as opposed to a true embracement of the open-source vision of developing things of value and let the developer decide."
Anne Thomas Manes, a Boston-based analyst with Burton Group Inc., echoed those sentiments.
"What bothers me is that I really dont like JAX-WS," Manes said. "The Sun JAX-WS team really needs to learn a few things from Microsoft. They should be building something like Indigo—a common programming model that encompasses JAX-WS/JAXM, JMS, RMI and EJB. But Sun doesnt get that."
However, "At least they made the jump from JAX-RPC to JAX-WS, and they arent afraid to break backward compatibility," Manes added. "But JAX-WS is still much too cumbersome—over-engineered in the traditional Sun engineering way."