Sun Microsystems’ former CEO, Jonathan Schwartz, says that Apple CEO Steve Jobs threatened to sue Sun for infringing on its intellectual property in 2003 for a user interface design.

According to “CNET” (, Jobs delivered his threat to Sun personally, Schwartz said, calling his office to say the graphics in Sun’s operating system 3D interface, Project Looking Glass, were “stepping all over Apple’s IP,” and that if Sun commercialized it, “I’ll just sue you.”

Sun countered with its own patent portfolio, according to “CNET.” With Apple, Schwartz raised the similarities between Apple’s Keynote presentation software and Concurrence, software from Schwartz’s start-up Lighthouse Design, which Sun acquired, the article says. And he pointed to Sun’s operating system patents, relevant given its Unix history and the fact that Apple’s Mac OS X uses Unix technology. “Steve was silent,” Schwartz said.