Sun Microsystems announced today the next version of Java will be Longhorn-ready.

While outlining the future of Java, executives at the annual JavaOne software developers conference in San Francisco told delegates the next release, code-named “Mustang”, will have native support for Longhorn in its graphical user interface (GUI) toolkit, dubbed Swing.

“We know many Java developers need to target Windows because that is important so we’re making sure Java Mustang runs really well and looks great on Longhorn,” Graham Hamilton, VP and fellow in the Java platform team at Sun, said.

With the release of Microsoft’s next generation operating system next year, Graham said Sun is already looking at the Longhorn build, to ensure “Swing applications will look good in Longhorn from day one”.

Swing has lagged behind in terms of flexibility, leaving many developers to move to a competing toolkit developed by IBM, and later given to the Eclipse foundation to be included in an IDE (integrated development environment) called SWT (Standard Widget Toolkit).

One of SWT’s advantages over Swing is when operating systems change, applications retain their original look and feel.

The two approaches to GUI design previously caused a rift between Sun and IBM, and the Java community as a whole.

Australian software developer Brandon Franklin says the announcement could be a blow to SWT.

“If Sun is already working on emulating Longhorn’s look and feel in Swing, then there is no “catch up” being played. They will be just as up-to-date as SWT on Longhorn,” Franklin told Builder AU.

However, Franklin warned that if Sun cannot deliver, the consequence will make little change to current development methods.

“Correctness in every detail is one of the SWT’s recognised advantages. If Swing’s Longhorn implementation isn’t perfect, then the SWT argument still holds at least some water.”

However, Sun’s Hamilton told developers at the conference that “out of the box when Longhorn ships, Java applications will look good from day one … it shouldn’t look like Windows XP apps running in Longhorn.”

Brendon Chase travelled to San Francisco as a guest of Sun Microsystems.