FFT Java Implementation Already Done

Hi. I'm looking for someone who has already implemented, and has, a Real-Time Fast Fourier Transform little App (not only library), to give to me. The first condition, is that the App can not be the "bewantbe" Audio Analyzer from GitHub. It has to be another FFT App which works correctly, preferably with Public License. The other conditions are that it needs to have a Refresh Rate of the Main Detected Frequency of at Least 15 Times a Second (0.66 miliseconds). And, the accuracy of the Frequency has to be greater than 70% of the Refreshed Results, from Guitar Played Notes, at Good Volume, with very low ambient sound. If someone posses an App like this, I expect your message. Thank you for your time. Have a good day.