Mixing
Dependency injection through constructor does not work for EJB bean
My app is being deployed on to IBM WebSphere. I have a simple service and I'd like to know how dependency injection works in this case.
// stateless EJB
@Stateless
public class UserService {
private UserDAO userDAO;
// btw, UserDAO is stateless EJB as well
@Inject
public UserService(UserDAO userDAO) {
this.userDAO = userDAO;
}
// biz methods ...
}
It fails with the following error:
[ERROR ] CWWKZ0002E: An exception occurred while starting the
application my-app. The exception message was:
com.ibm.ws.container.service.state.StateChangeException:
com.ibm.ws.cdi.CDIException:
com.ibm.wsspi.injectionengine.InjectionException:
com.ibm.ejs.container.EJBConfigurationException: EJB class
com.demo.app.UserService must have a
public constructor that takes no parameters
I remember there was something in EJB spec that says: the class must have a public constructor that takes no parameters and it makes sense for me that the bean instance is first instantiated by the container and afterward dependency injection is done.
On the other hand, I've found this in WELD docs:
First, the container calls the bean constructor (the default
constructor or the one annotated @Inject), to obtain an instance of
the bean.
And I am confused a little bit, why my EJB cannot be instantiated.
How is the EJB instance being created and dependencies injected when we have constructor injection point?
Any ideas? :)
java java-ee dependency-injection ejb weld
asked Nov 19 '18 at 14:27
john
1,50551827
add a comment |
My app is being deployed on to IBM WebSphere. I have a simple service and I'd like to know how dependency injection works in this case.
// stateless EJB
@Stateless
public class UserService {
private UserDAO userDAO;
// btw, UserDAO is stateless EJB as well
@Inject
public UserService(UserDAO userDAO) {
this.userDAO = userDAO;
}
// biz methods ...
}
It fails with the following error:
[ERROR ] CWWKZ0002E: An exception occurred while starting the
application my-app. The exception message was:
com.ibm.ws.container.service.state.StateChangeException:
com.ibm.ws.cdi.CDIException:
com.ibm.wsspi.injectionengine.InjectionException:
com.ibm.ejs.container.EJBConfigurationException: EJB class
com.demo.app.UserService must have a
public constructor that takes no parameters
I remember there was something in EJB spec that says: the class must have a public constructor that takes no parameters and it makes sense for me that the bean instance is first instantiated by the container and afterward dependency injection is done.
On the other hand, I've found this in WELD docs:
First, the container calls the bean constructor (the default
constructor or the one annotated @Inject), to obtain an instance of
the bean.
And I am confused a little bit, why my EJB cannot be instantiated.
How is the EJB instance being created and dependencies injected when we have constructor injection point?
Any ideas? :)
java java-ee dependency-injection ejb weld
asked Nov 19 '18 at 14:27
john
1,50551827
add a comment |
My app is being deployed on to IBM WebSphere. I have a simple service and I'd like to know how dependency injection works in this case.
// stateless EJB
@Stateless
public class UserService {
private UserDAO userDAO;
// btw, UserDAO is stateless EJB as well
@Inject
public UserService(UserDAO userDAO) {
this.userDAO = userDAO;
}
// biz methods ...
}
It fails with the following error:
[ERROR ] CWWKZ0002E: An exception occurred while starting the
application my-app. The exception message was:
com.ibm.ws.container.service.state.StateChangeException:
com.ibm.ws.cdi.CDIException:
com.ibm.wsspi.injectionengine.InjectionException:
com.ibm.ejs.container.EJBConfigurationException: EJB class
com.demo.app.UserService must have a
public constructor that takes no parameters
I remember there was something in EJB spec that says: the class must have a public constructor that takes no parameters and it makes sense for me that the bean instance is first instantiated by the container and afterward dependency injection is done.
On the other hand, I've found this in WELD docs:
First, the container calls the bean constructor (the default
constructor or the one annotated @Inject), to obtain an instance of
the bean.
And I am confused a little bit, why my EJB cannot be instantiated.
How is the EJB instance being created and dependencies injected when we have constructor injection point?
Any ideas? :)
java java-ee dependency-injection ejb weld
asked Nov 19 '18 at 14:27
john
1,50551827
My app is being deployed on to IBM WebSphere. I have a simple service and I'd like to know how dependency injection works in this case.
// stateless EJB
@Stateless
public class UserService {
private UserDAO userDAO;
// btw, UserDAO is stateless EJB as well
@Inject
public UserService(UserDAO userDAO) {
this.userDAO = userDAO;
}
// biz methods ...
}
It fails with the following error:
[ERROR ] CWWKZ0002E: An exception occurred while starting the
application my-app. The exception message was:
com.ibm.ws.container.service.state.StateChangeException:
com.ibm.ws.cdi.CDIException:
com.ibm.wsspi.injectionengine.InjectionException:
com.ibm.ejs.container.EJBConfigurationException: EJB class
com.demo.app.UserService must have a
public constructor that takes no parameters
I remember there was something in EJB spec that says: the class must have a public constructor that takes no parameters and it makes sense for me that the bean instance is first instantiated by the container and afterward dependency injection is done.
On the other hand, I've found this in WELD docs:
First, the container calls the bean constructor (the default
constructor or the one annotated @Inject), to obtain an instance of
the bean.
And I am confused a little bit, why my EJB cannot be instantiated.
How is the EJB instance being created and dependencies injected when we have constructor injection point?
Any ideas? :)
java java-ee dependency-injection ejb weld
java java-ee dependency-injection ejb weld
asked Nov 19 '18 at 14:27
john
1,50551827
asked Nov 19 '18 at 14:27
john
1,50551827
edited Nov 19 '18 at 14:32
asked Nov 19 '18 at 14:27
john
1,50551827
asked Nov 19 '18 at 14:27
john
1,50551827
asked Nov 19 '18 at 14:27
john
1,50551827
1,50551827
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
So what happens is that you do not meet the requirements for initializing EJB beans.
CDI spec has some limitations on constructors - either no-args or one with @Inject.
But there is also this chapter, which specifies that in EE, the set of rules is extended by what EJB session beans require.
And now we are getting into EJB spec which requires a no-arg constructor on a bean.
This should be in chapter Enterprise Bean Class where it states
The class must define a public constructor that takes no arguments.
Now, finally moving on to whether this should work - e.g. can you have an EJB bean using CDI constructor injection?
Well, let's have a look at CDI TCK, a set of tests that all implementation and containers have to pass in order to be able to claim they implement CDI.
There, we can see this bean and this test using it - so yea, this can work, but you need to have both constructors.
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
add a comment |
the creation of EJB session beans is done by EJB container but it can choose to use CDI to provide EE resource injection but EJB resolution is delegated to the container
https://docs.jboss.org/weld/reference/2.1.0.Final/en-US/html/ri-spi.html says:
Alternatively, the integrator may choose to use CDI to provide EE
resource injection. In this case, the EE_INJECT environment should be
used, and the integrator should implement the Section A.1.4, “EJB
services”, Section A.1.7, “Resource Services” and Section A.1.5, “JPA
services”.
....
Weld registers resource injection points with
EjbInjectionServices, JpaInjectionServices, ResourceInjectionServices
and JaxwsInjectionServices implementations upfront (at bootstrap).
This allows validation of resource injection points to be performed at
boot time rather than runtime
if you interested in how CDI and EJB are integrated. you can have a look at the code of weld-EJB module and weld-integration(glassfish code)
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
add a comment |
EJBs are registered as CDI beans. But first they have to meet the requirements of the EJB spec.
I guess it works just by providing the no-args constructor.
answered Nov 19 '18 at 15:08
Frito
3369
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
So what happens is that you do not meet the requirements for initializing EJB beans.
CDI spec has some limitations on constructors - either no-args or one with @Inject.
But there is also this chapter, which specifies that in EE, the set of rules is extended by what EJB session beans require.
And now we are getting into EJB spec which requires a no-arg constructor on a bean.
This should be in chapter Enterprise Bean Class where it states
The class must define a public constructor that takes no arguments.
Now, finally moving on to whether this should work - e.g. can you have an EJB bean using CDI constructor injection?
Well, let's have a look at CDI TCK, a set of tests that all implementation and containers have to pass in order to be able to claim they implement CDI.
There, we can see this bean and this test using it - so yea, this can work, but you need to have both constructors.
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
add a comment |
So what happens is that you do not meet the requirements for initializing EJB beans.
CDI spec has some limitations on constructors - either no-args or one with @Inject.
But there is also this chapter, which specifies that in EE, the set of rules is extended by what EJB session beans require.
And now we are getting into EJB spec which requires a no-arg constructor on a bean.
This should be in chapter Enterprise Bean Class where it states
The class must define a public constructor that takes no arguments.
Now, finally moving on to whether this should work - e.g. can you have an EJB bean using CDI constructor injection?
Well, let's have a look at CDI TCK, a set of tests that all implementation and containers have to pass in order to be able to claim they implement CDI.
There, we can see this bean and this test using it - so yea, this can work, but you need to have both constructors.
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
add a comment |
So what happens is that you do not meet the requirements for initializing EJB beans.
CDI spec has some limitations on constructors - either no-args or one with @Inject.
But there is also this chapter, which specifies that in EE, the set of rules is extended by what EJB session beans require.
And now we are getting into EJB spec which requires a no-arg constructor on a bean.
This should be in chapter Enterprise Bean Class where it states
The class must define a public constructor that takes no arguments.
Now, finally moving on to whether this should work - e.g. can you have an EJB bean using CDI constructor injection?
Well, let's have a look at CDI TCK, a set of tests that all implementation and containers have to pass in order to be able to claim they implement CDI.
There, we can see this bean and this test using it - so yea, this can work, but you need to have both constructors.
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
So what happens is that you do not meet the requirements for initializing EJB beans.
CDI spec has some limitations on constructors - either no-args or one with @Inject.
But there is also this chapter, which specifies that in EE, the set of rules is extended by what EJB session beans require.
And now we are getting into EJB spec which requires a no-arg constructor on a bean.
This should be in chapter Enterprise Bean Class where it states
The class must define a public constructor that takes no arguments.
Now, finally moving on to whether this should work - e.g. can you have an EJB bean using CDI constructor injection?
Well, let's have a look at CDI TCK, a set of tests that all implementation and containers have to pass in order to be able to claim they implement CDI.
There, we can see this bean and this test using it - so yea, this can work, but you need to have both constructors.
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
answered Nov 20 '18 at 11:44
Siliarus
3,6871519
3,6871519
add a comment |
add a comment |
the creation of EJB session beans is done by EJB container but it can choose to use CDI to provide EE resource injection but EJB resolution is delegated to the container
https://docs.jboss.org/weld/reference/2.1.0.Final/en-US/html/ri-spi.html says:
Alternatively, the integrator may choose to use CDI to provide EE
resource injection. In this case, the EE_INJECT environment should be
used, and the integrator should implement the Section A.1.4, “EJB
services”, Section A.1.7, “Resource Services” and Section A.1.5, “JPA
services”.
....
Weld registers resource injection points with
EjbInjectionServices, JpaInjectionServices, ResourceInjectionServices
and JaxwsInjectionServices implementations upfront (at bootstrap).
This allows validation of resource injection points to be performed at
boot time rather than runtime
if you interested in how CDI and EJB are integrated. you can have a look at the code of weld-EJB module and weld-integration(glassfish code)
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
add a comment |
the creation of EJB session beans is done by EJB container but it can choose to use CDI to provide EE resource injection but EJB resolution is delegated to the container
https://docs.jboss.org/weld/reference/2.1.0.Final/en-US/html/ri-spi.html says:
Alternatively, the integrator may choose to use CDI to provide EE
resource injection. In this case, the EE_INJECT environment should be
used, and the integrator should implement the Section A.1.4, “EJB
services”, Section A.1.7, “Resource Services” and Section A.1.5, “JPA
services”.
....
Weld registers resource injection points with
EjbInjectionServices, JpaInjectionServices, ResourceInjectionServices
and JaxwsInjectionServices implementations upfront (at bootstrap).
This allows validation of resource injection points to be performed at
boot time rather than runtime
if you interested in how CDI and EJB are integrated. you can have a look at the code of weld-EJB module and weld-integration(glassfish code)
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
add a comment |
the creation of EJB session beans is done by EJB container but it can choose to use CDI to provide EE resource injection but EJB resolution is delegated to the container
https://docs.jboss.org/weld/reference/2.1.0.Final/en-US/html/ri-spi.html says:
Alternatively, the integrator may choose to use CDI to provide EE
resource injection. In this case, the EE_INJECT environment should be
used, and the integrator should implement the Section A.1.4, “EJB
services”, Section A.1.7, “Resource Services” and Section A.1.5, “JPA
services”.
....
Weld registers resource injection points with
EjbInjectionServices, JpaInjectionServices, ResourceInjectionServices
and JaxwsInjectionServices implementations upfront (at bootstrap).
This allows validation of resource injection points to be performed at
boot time rather than runtime
if you interested in how CDI and EJB are integrated. you can have a look at the code of weld-EJB module and weld-integration(glassfish code)
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
the creation of EJB session beans is done by EJB container but it can choose to use CDI to provide EE resource injection but EJB resolution is delegated to the container
https://docs.jboss.org/weld/reference/2.1.0.Final/en-US/html/ri-spi.html says:
Alternatively, the integrator may choose to use CDI to provide EE
resource injection. In this case, the EE_INJECT environment should be
used, and the integrator should implement the Section A.1.4, “EJB
services”, Section A.1.7, “Resource Services” and Section A.1.5, “JPA
services”.
....
Weld registers resource injection points with
EjbInjectionServices, JpaInjectionServices, ResourceInjectionServices
and JaxwsInjectionServices implementations upfront (at bootstrap).
This allows validation of resource injection points to be performed at
boot time rather than runtime
if you interested in how CDI and EJB are integrated. you can have a look at the code of weld-EJB module and weld-integration(glassfish code)
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
edited Nov 20 '18 at 13:07
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
answered Nov 20 '18 at 6:53
Mehran Mastcheshmi
3981210
3981210
add a comment |
add a comment |
EJBs are registered as CDI beans. But first they have to meet the requirements of the EJB spec.
I guess it works just by providing the no-args constructor.
answered Nov 19 '18 at 15:08
Frito
3369
add a comment |
EJBs are registered as CDI beans. But first they have to meet the requirements of the EJB spec.
I guess it works just by providing the no-args constructor.
answered Nov 19 '18 at 15:08
Frito
3369
add a comment |
EJBs are registered as CDI beans. But first they have to meet the requirements of the EJB spec.
I guess it works just by providing the no-args constructor.
answered Nov 19 '18 at 15:08
Frito
3369
EJBs are registered as CDI beans. But first they have to meet the requirements of the EJB spec.
I guess it works just by providing the no-args constructor.
answered Nov 19 '18 at 15:08
Frito
3369
answered Nov 19 '18 at 15:08
Frito
3369
answered Nov 19 '18 at 15:08
Frito
3369
answered Nov 19 '18 at 15:08
Frito
3369
3369
add a comment |
add a comment |
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