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What can AOP do that OOP can't do?
public void saveMyEntityToTheDatabase(MyEntity entity) {
    EntityTransaction tx = null;
    try {
        tx = entityManager.getTransaction();
        tx.begin();
        entityManager.persist(entity);
        tx.commit();
    } catch (RuntimeException e) {
        if(tx != null && tx.isActive()) {
            tx.rollback();
        }
        throw e;
    }
}

@Transactional
public void saveMyEntityToTheDatabase(MyEntity entity) {
    entityManager.persist(entity);
}

public void saveMyEntityToTheDatabase(MyEntity entity) {
    database.performInTransaction(new Save(entity));
}

@Transactional
public Employee hire(Person p, Employee manager, BigDecimal salary) {
    // implementation omitted
}

Employee hired = service.hire(candidate, manager, agreedOnSalary);

class HireAction implements Callable<Employee> {
    private final Person person;
    private final Employee manager;
    private final BigDecimal salary;

    public HireAction(Person person, Employee manager, BigDecimal salary) {
        this.person = person;
        this.manager = manager;
        this.salary = salary;
    }

    @Override
    public Employee call() throws Exception {
        // implementation omitted
    }
}

Employee hired = session.doInTransaction(new HireAction(candidate, manager, agreedOnSalary));

class HRService {
    class HireAction {
        // impl omitted
    }
    class FireAction {
        // impl omitted
    }
}

Employee emp = session.doInTransaction(new HRService().new HireAction(candidate, manager, salary));

Employee e = new HireAction(candidate, manager, salary).call();