A US federal appeals court yesterday stayed a judge's order requiring Microsoft to ship Sun's Java technology with its Windows operating system.

The Court of Appeals halted an order that would have gone into effect Tuesday requiring Microsoft to offer Sun's Java Runtime Environment with Windows XP and Internet Explorer. The appeals court ruling ran to about two pages and offered little explanation for the stay, according to a Sun representative.

It delays, pending action by the appeals court, a December 23 order by District Court Judge Frederick Motz, who is presiding over a number of private antitrust lawsuits against Microsoft including one filed by Sun. Motz set the clock ticking on the "must-carry" Java order in a ruling January 21, when he gave Microsoft 120 days to comply.

Sun has argued that Microsoft tried to derail a competitive threat posed by Java by offering a version of the technology that is incompatible with Sun's specifications. Its lawyers argued before Motz that Microsoft's behavior, if allowed to continue, would unfairly drive developers to Microsoft's competing .Net platform.

"We regret the Fourth Circuit Court's decision," Lee Patch, vice president for legal affairs at Sun, said in a statement. "The preliminary injunctions granted by the District Court will benefit consumers and the Java Community's developers, enterprises and system vendors. We will work actively to ensure that the earliest possible date is set for the appellate hearing. We look forward to demonstrating the merits of District Court's decision when the appeal is heard."

Earlier yesterday, Microsoft said it was taking steps to comply with Motz's order, by replacing the service pack Windows XP SP1 with a new service pack, XP SP1a. The upgrade is identical to the previous service pack but excludes Microsoft's Java virtual machine. Microsoft had planned to include Sun's Java software in Windows XP in early June 2003 starting with Service Pack 1b.

Microsoft spokesman Jim Desler said later on Monday that the company would continue with its plans to distribute the new service pack without Microsoft's version of Java. But other plans to comply with Motz's order are now on hold pending further appeals court action.

"We're pleased the court granted our motion, but the work that we did up to this point revealed that we were complying fully with the district court order," Desler said. "We will continue the process to get out of the Java business in a way that allows us to support and minimize any impact on our customers. SP1a will continue to be available to customers on Windows Update and we will no longer include the MS (version of Java) in any Microsoft product moving forward."