anchor.diff:  every time a lesson is assigned to a different time slot or room,
   all lessons are re-evaluated to calculate the new score.
   
  -Instead, create a `src/main/java/org/acme/solver/TimeTableConstraintProvider.java` class
  +Instead, create a `src/main/java/org/acme/optaplanner/solver/TimeTableConstraintProvider.java` class
   to perform incremental score calculation.
   It uses OptaPlanner's ConstraintStream API which is inspired by Java 8 Streams and SQL:
   
   [source,java]
   ----
  -package org.acme.solver;
  -
  -import org.acme.domain.Lesson;
  +package org.acme.optaplanner.solver;
  +
  +import org.acme.optaplanner.domain.Lesson;
   import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScore;
   import org.optaplanner.core.api.score.stream.Constraint;
   import org.optaplanner.core.api.score.stream.ConstraintFactory;
  
positive.code: For simplicity's sake, all rooms are without capacity limits
  and they can accommodate all lessons.
  
  Create the `src/main/java/org/acme/domain/Room.java` class:
  
  [source,java]
  ----
  package org.acme.domain;
  
  public class Room {
  
  
negative.code: import javax.ws.rs.Produces;
  import javax.ws.rs.core.MediaType;
  
  import org.acme.optaplanner.domain.TimeTable;
  import org.optaplanner.core.api.solver.SolverJob;
  import org.optaplanner.core.api.solver.SolverManager;
  
  