Compilation and running

Unpack the jar file with jar -xf sudokusrc.jar into your working directory. Then compile all Java files with a java compiler. (javac *.java on some systems, or even just javac SudokuUI on others) and then run the SudokuUI class using java SudokuUI
Replace javac with the relevant compiler if you are using different java compilers.

The file sudoku.jar contains the compiled class files (compiled with javac in j2sdk1.4.01), so you can simply set the classpath to include this jar file and java SudokuUI. On my system this is simply java -cp sudoku.jar SudokuUI

Time issues.

In general the program runs quickly under j2sdk1.4. The main issue is with generation, which calls the solve routine multiple times (and I am talking of many hundreds with 25x25 puzzle generation).
On my 2G Pentium 4 it may take a few minutes to generate a VH symmetric 25x25 puzzle.
Generating a puzzle with less symmetry takes longer. 9x9 puzzles take a few seconds (one or two) and 16x16 takes five to ten seconds.
These times do vary with the interpreter being used.

Compatibilty issues