spring injection java.lang.NullPointerException - spring

Question

when I have injected the been AdminService the java.lang.NullPointerException appeared , although I inject this bean with the same way in another managed bean and everything works :
#ManagedBean
#SessionScoped
public class ScheduleController implements Serializable {
/**
*
*/
private static final long serialVersionUID = -1489523494215832724L;
private ScheduleModel eventModel;
#ManagedProperty(value = "#{adminService}")
AdminService adminService;
private ScheduleEvent event = new DefaultScheduleEvent();
public ScheduleController() {
List<Service> = adminService.getAllService();
}
public AdminService getAdminService() {
return adminService;
}
public void setAdminService(AdminService adminService) {
this.adminService = adminService;
}
AdminService implementation:
Service("adminService")
public class AdminServiceImpl implements AdminService,Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Autowired
AdminDao adminDao ;
// adminDao injected by spring
#Transactional
public void add(Admin admin) {
adminDao.save(admin);
}
#Transactional
public void edit(Admin admin) {
adminDao.update(admin);
}
#Transactional
public void delete(Admin admin) {
adminDao.delete(admin);
}
#Transactional
public Admin getAdmin(Integer adminId) {
return adminDao.findById(adminId);
}
#Transactional
public List<Admin> getAllAdmin() {
return adminDao.findAll();
}
/**
* #return the adminDao
*/
public AdminDao getAdminDao() {
return adminDao;
}
/**
* #param adminDao the adminDao to set
*/
public void setAdminDao(AdminDao adminDao) {
this.adminDao = adminDao;
}
#Override
public Admin authenticate(String adminName, String adminPass) {
return this.adminDao.authenticate(adminName, adminPass);
}
}

Answer 1

You're trying to access the injected dependency during construction of the bean. This is obviously not going to work. You're basically expecting that it all works like follows under the covers:
ScheduleController scheduleController; // Declare.
scheduleController.adminService = new AdminService(); // Inject.
scheduleController = new ScheduleController(); // Construct.
This makes no sense. It's not possible to set an instance variable before the instance is constructed. Instead, it works like follows:
ScheduleController scheduleController; // Declare.
scheduleController = new ScheduleController(); // Construct.
scheduleController.adminService = new AdminService(); // Inject.
If you'd like to perform an action directly after construction and injection, then you should be using a #PostConstruct annotated method.
So, replace
public ScheduleController() {
List<Service> services = adminService.getAllService();
}
by
#PostConstruct
public void init() { // Note: method name is fully free to your choice.
List<Service> services = adminService.getAllService();
}
No need for the <f:event> mess. It also doesn't necessarily need to go in <f:metadata> by the way.

Answer 2

i find the solution , the problem is not a problem of injection is a problem of call, I worked with this ways, and it works :
in the managed bean i add a init method :
public void init(){
List<Service> = adminService.getAllService();
}
and in the page.xhtml :
<f:metadata>
<f:event type="preRenderView" listener="#{scheduleController.init()}"/>
</f:metadata>