The optaplanner-training teaches OptaPlanner through a number of labs. Each lab has an assignment with clear goals, initial code and a solution.
optaplanner-training-*.zip is publicly available to the community.
It’s unclear if that will remain the case. Grab it while you can :)
Download and unzip
instructions/training.html and follow those instructions.
The source code which generates that training zip is in the optaplanner-training GitHub repository.