This is a Java implementation of Classical 8-queen problem proposed by Gauss, C.F. Three presentations are provided in this implementation (4 to 16 queens are supported in this program) -1. Solution only: This is because the moving of the backtracking takes a lot of time, so the brief solutions are provided instead.2. The backtracking version of the program. This shows the moving of the backtracking process.3. 5 queens to be placed on an 8×8 board so that no two queens attack each other, and no extra new queens could be placed on board.Come join us on FaceBook’s YPK Android Software.Update history -1.4 use 12-key numeric keypad to enter numbers.1.3 made some changes on the input interface.1.2 add unique solutions to 5 queens on 8×8 board.1.1 add 5 queens on 8×8 chess board – distinct solutions.1.0 initial version – 4-16 queens problems.