Sun Microsystems may have dropped a bit of weight by the time Oracle officially acquires the company. According to two people briefed on Sun’s plans, the company has cancelled its Rock chip project, putting an end to one of its biggest revitalization bets. Sun has been working on the Rock project for more than five years, hoping to create a chip with many cores that would trounce competing server chips from IBM. and Intel. The company has talked about Rock in the loftiest of terms and built it up as a game-changing product. In April 2007, Jonathan Schwartz, the chief executive of Sun, bragged about receiving the first test versions of Rock. But the two people familiar with Sun’s plans say Rock has met with an unceremonious end. The people requested anonymity, as they are not authorized to speak with the press about Sun’s plans. Michelle Parkinson, a Sun spokeswoman, said the company had no comment.