Question

I have a question regarding declaration of classes in applicationContext.xml

In applicationContext.xml do we need to specify all the classes from the application?
E.g.
In my small web application I have a Entity class, Service class and DAO class. So currently it is defined as

<!-- Beans Declaration -->
    <bean id="Employees"
        class="net.test.model.Employees" />

 <!-- User Service Declaration -->
    <bean id="
        EmployeeService" class="net.test.employees.service.EmployeeService">
        <property name="employeesDAO" ref="EmployeeDAOImpl" />
    </bean>

 <!-- User DAO Declaration -->
    <bean id="EmployeeDAO" class="net.test.employee.dao.EmployeeDAOImpl">
        <property name="sessionFactory" ref="SessionFactory" />
    </bean>

So if I have multiple entity, service and dao classes do I need to mention all those classes in applicationContext.xml?

Any insight into this is highly appreciable.

Regards

Update 1

ManagedBean

@ManagedBean(name="empMB")
@Named
@Scope("request")
public class EmployeesManagedBean implements Serializable {

and I have Inject annotation

@Inject
EmployeesService employeesService;

In EmployeesService I have annotations like

@Named
public class EmployeesService implements IEmployeesService {

@Inject
EmployeesDAO employeesDAO;

@Override
public List<Employees> getEmployees() {
    return getEmployeesDAO().getEmployees();
}

and finally in applicationContext.xml I have

<context:component-scan base-package="net.test" />

Now the problem is when I run my application I am getting

java.lang.NullPointerException at
net.test.managed.bean.EmployeesManagedBean.getEmpList(EmployeesManagedBean.java:53)

What am I doing wrongly to get nullpointer exception?

Answer 1

In applicationContext.xml do we need to specify all the classes from
the application?

No. Declaring model classes like your net.test.model.Employees is pointless unless you need a prototype to work with, something like initializing its values, but you can do this directly in the class and just instantiate it.

So if I have multiple entity, service and dao classes do I need to
mention all those classes in applicationContext.xml?

As I explained before, entity classes no. Services and DAOs are ok because most of the time you need DAOs injected to the Services (and that’s the point of DI). But of course, if you create 3 DAOs and you want them to be injected in your 3 Services, then mention them in your Spring XML Bean Definition file (what you call applicationContext.xml).

But one thing, you may want to use package scanning autodetection and annotation based config to avoid writing everything in your Bean Definition File.