I've found the following information in Sinodefence-
In 1997, the U.S. Office of Naval Intelligence (ONI) reported that an advanced F-22-class twin-engine stealth fighter XXJ was being developed by 601 Institute and Shenyang Aircraft Corporation (SAC). In 2001, an Internet source photo showed a F-22-like aircraft model was being tested in a wind tunnel at 601 Institute. At the same time, it was revealed that 611 Institute was also working its own advanced fighter aircraft design, possibly based on the design and technology of its J-10 fighter.
There has been speculations Chinas fourth-generation fighter could enter service as early as 2015. However, designing and developing a fighter of this class will involve huge amount of investment and technology advancement across many fields, including new materials, high-performance aero-engine, avionics, flight control software, stealth technology, computer-aid design and manufacture (CAD/CAM).
Russian Sukhoi Company (JSC), which has developed close ties with Shenyang over the licensed co-production of its Su-27SK fighter as J-11, has been reportedly working with Shenyang in developing the next-generation fighter technology and sub-systems.