Sun and its StorageTek unit are being sued for copyright infringement and fraud by Californian company Netbula.

Netbula offers Internet development tools and its suing both companies for unlawful use of Netbula's core technology in their LibAttach software. Netbula also claims that Sun and StorageTek breached a contract Netbula has with the companies and misrepresented their use of Netbula's technology, part of its main product line PowerRPC. PowerRPC is a cross-platform client/server development kit for various versions of Windows, as well as for Unix and Java.

Sun purchased StorageTek in June 2005, but Netbula is suing the two as separate companies because the copyright infringement began when they were still individual entities, said Vonnah Brillet, the lawyer handling the case for Netbula.

Brillet said Netbula's president Don Yue developed software and sold a licence for it to StorageTek when it was a standalone company. At one point when he asked about whether StorageTek was still using the technology, he was told the company was not, she said.

However, an unspecified time after that, someone from StorageTek asked Yue for updates to the technology, which proved that the company was still using it, but not paying for the licence, Brillet said.

Netbula tried to resolve the issue with Sun before filing the suit to no avail, the company said. It is seeking an injunction to stop Sun and StorageTek from using its technology. The lawsuit also seeks financial restitution.

Sun is currently embroiled in another intellectual property suit over patents. Earlier this year, startup company Azul sued the vendor in a defensive move after Sun threatened the company with litigation for patent infringement and misappropriation of trade secrets.

Azul called Sun's charges unfounded and sued for declaratory relief against the accusations and the threat of litigation. Azul said Sun would file a lawsuit unless Azul granted Sun partial ownership of the company. Sun eventually counter-sued Azul in May for patent infringement. The cases are still pending in California.