The suit, filed in U.S. District Court in San Jose, Calif., seeks to force Microsoft to pay undisclosed damages, release the underlying source code for Internet Explorer, and release interfaces between Windows and higher-level Microsoft software. The suit also seeks preliminary injunctions to require Microsoft to ship Java with Windows XP and Internet Explorer.
AOL Time Warnera similar suit against Microsoft in January.
Microsoft didn't immediately respond to a call for comment.
At the center of the case is Sun's Java software, which lets programs run on many types of computers without having to be modified for each one.
MicrosoftJava out of Internet Explorer when it launched its new Windows XP operating system last fall. Microsoft said at the time that it feared that including the software could spur Sun to try to of XP through legal action.