The behavior is always the same so the isReinitialized() method can be simplified from

public boolean isReinitializable(ScoreDirector<Solution_> scoreDirector, Object entity) {
    return reinitializeVariableEntityFilter.accept(scoreDirector, entity);
}

public boolean isReinitializable(Object entity) {
    return getValue(entity) == null;
}

• NullValueReinitializeVariableEntityFilter class can be deleted.
• isReinitialized() no longer needs ScoreDirector. This has implications up to DefaultExhaustiveSearchPhase.
• Unit tests needs to preserved!