Why is my Spring @Autowired field null?

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Note: This is intended to be a canonical answer for a common problem.

I have a Spring @Service class (MileageFeeCalculator) that has an @Autowired field (rateService), but the field is null when I try to use it. The logs show that both the MileageFeeCalculator bean and the MileageRateService bean are being created, but I get a NullPointerException whenever I try to call the mileageCharge method on my service bean. Why isn't Spring autowiring the field?

Controller class:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = new MileageFeeCalculator();

        return calc.mileageCharge(miles);

    }

}

Service class:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- should be autowired, is null



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); // <--- throws NPE

    }

}

Service bean that should be autowired in MileageFeeCalculator but it isn't:

@Service

public class MileageRateService {

    public float ratePerMile() {

        return 0.565f;

    }

}

When I try to GET /mileage/3, I get this exception:

java.lang.NullPointerException: null

    at com.chrylis.example.spring_autowired_npe.MileageFeeCalculator.mileageCharge(MileageFeeCalculator.java:13)

    at com.chrylis.example.spring_autowired_npe.MileageFeeController.mileageFee(MileageFeeController.java:14)

    ...

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

Another scenario can be when bean F is called inside the constructor of another bean S. In this case pass the required bean F as a parameter to the other beans S constructor and annotate the constructor of S with @Autowire. Remember to annotate the class of the first bean F with @Component.
– aliopi
Nov 11 '15 at 12:36

I coded up a few examples very similar to this one using Gradle here: github.com/swimorsink/spring-aspectj-examples. Hopefully someone will find it useful.
– Ross117
Nov 14 at 2:33

add a comment |

up vote
470
down vote

favorite

167

Note: This is intended to be a canonical answer for a common problem.

Controller class:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = new MileageFeeCalculator();

        return calc.mileageCharge(miles);

    }

}

Service class:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- should be autowired, is null



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); // <--- throws NPE

    }

}

Service bean that should be autowired in MileageFeeCalculator but it isn't:

@Service

public class MileageRateService {

    public float ratePerMile() {

        return 0.565f;

    }

}

When I try to GET /mileage/3, I get this exception:

java.lang.NullPointerException: null

    at com.chrylis.example.spring_autowired_npe.MileageFeeCalculator.mileageCharge(MileageFeeCalculator.java:13)

    at com.chrylis.example.spring_autowired_npe.MileageFeeController.mileageFee(MileageFeeController.java:14)

    ...

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

Another scenario can be when bean F is called inside the constructor of another bean S. In this case pass the required bean F as a parameter to the other beans S constructor and annotate the constructor of S with @Autowire. Remember to annotate the class of the first bean F with @Component.
– aliopi
Nov 11 '15 at 12:36

I coded up a few examples very similar to this one using Gradle here: github.com/swimorsink/spring-aspectj-examples. Hopefully someone will find it useful.
– Ross117
Nov 14 at 2:33

add a comment |

up vote
470
down vote

favorite

167

up vote
470
down vote

favorite

167

Note: This is intended to be a canonical answer for a common problem.

Controller class:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = new MileageFeeCalculator();

        return calc.mileageCharge(miles);

    }

}

Service class:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- should be autowired, is null



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); // <--- throws NPE

    }

}

Service bean that should be autowired in MileageFeeCalculator but it isn't:

@Service

public class MileageRateService {

    public float ratePerMile() {

        return 0.565f;

    }

}

When I try to GET /mileage/3, I get this exception:

java.lang.NullPointerException: null

    at com.chrylis.example.spring_autowired_npe.MileageFeeCalculator.mileageCharge(MileageFeeCalculator.java:13)

    at com.chrylis.example.spring_autowired_npe.MileageFeeController.mileageFee(MileageFeeController.java:14)

    ...

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

Note: This is intended to be a canonical answer for a common problem.

Controller class:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = new MileageFeeCalculator();

        return calc.mileageCharge(miles);

    }

}

Service class:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- should be autowired, is null



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); // <--- throws NPE

    }

}

Service bean that should be autowired in MileageFeeCalculator but it isn't:

@Service

public class MileageRateService {

    public float ratePerMile() {

        return 0.565f;

    }

}

When I try to GET /mileage/3, I get this exception:

java.lang.NullPointerException: null

    at com.chrylis.example.spring_autowired_npe.MileageFeeCalculator.mileageCharge(MileageFeeCalculator.java:13)

    at com.chrylis.example.spring_autowired_npe.MileageFeeController.mileageFee(MileageFeeController.java:14)

    ...

java spring null nullpointerexception autowired

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

edited Mar 22 '17 at 16:24

Taryn♦

187k45284348

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

asked Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

Another scenario can be when bean F is called inside the constructor of another bean S. In this case pass the required bean F as a parameter to the other beans S constructor and annotate the constructor of S with @Autowire. Remember to annotate the class of the first bean F with @Component.
– aliopi
Nov 11 '15 at 12:36

I coded up a few examples very similar to this one using Gradle here: github.com/swimorsink/spring-aspectj-examples. Hopefully someone will find it useful.
– Ross117
Nov 14 at 2:33

add a comment |

1

Another scenario can be when bean F is called inside the constructor of another bean S. In this case pass the required bean F as a parameter to the other beans S constructor and annotate the constructor of S with @Autowire. Remember to annotate the class of the first bean F with @Component.
– aliopi
Nov 11 '15 at 12:36

I coded up a few examples very similar to this one using Gradle here: github.com/swimorsink/spring-aspectj-examples. Hopefully someone will find it useful.
– Ross117
Nov 14 at 2:33

Another scenario can be when bean F is called inside the constructor of another bean S. In this case pass the required bean F as a parameter to the other beans S constructor and annotate the constructor of S with @Autowire. Remember to annotate the class of the first bean F with @Component.
– aliopi
Nov 11 '15 at 12:36

I coded up a few examples very similar to this one using Gradle here: github.com/swimorsink/spring-aspectj-examples. Hopefully someone will find it useful.
– Ross117
Nov 14 at 2:33

add a comment |

12 Answers
12

active

oldest

votes

up vote
522
down vote

accepted

The field annotated @Autowired is null because Spring doesn't know about the copy of MileageFeeCalculator that you created with new and didn't know to autowire it.

The Spring Inversion of Control (IoC) container has three main logical components: a registry (called the ApplicationContext) of components (beans) that are available to be used by the application, a configurer system that injects objects' dependencies into them by matching up the dependencies with beans in the context, and a dependency solver that can look at a configuration of many different beans and determine how to instantiate and configure them in the necessary order.

The IoC container isn't magic, and it has no way of knowing about Java objects unless you somehow inform it of them. When you call new, the JVM instantiates a copy of the new object and hands it straight to you--it never goes through the configuration process. There are three ways that you can get your beans configured.

I have posted all of this code, using Spring Boot to launch, at this GitHub project; you can look at a full running project for each approach to see everything you need to make it work. Tag with the NullPointerException: nonworking

Inject your beans

The most preferable option is to let Spring autowire all of your beans; this requires the least amount of code and is the most maintainable. To make the autowiring work like you wanted, also autowire the MileageFeeCalculator like this:

@Controller

public class MileageFeeController {



    @Autowired

    private MileageFeeCalculator calc;



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

If you need to create a new instance of your service object for different requests, you can still use injection by using the Spring bean scopes.

Tag that works by injecting the @MileageFeeCalculator service object: working-inject-bean

Use @Configurable

If you really need objects created with new to be autowired, you can use the Spring @Configurable annotation along with AspectJ compile-time weaving to inject your objects. This approach inserts code into your object's constructor that alerts Spring that it's being created so that Spring can configure the new instance. This requires a bit of configuration in your build (such as compiling with ajc) and turning on Spring's runtime configuration handlers (@EnableSpringConfigured with the JavaConfig syntax). This approach is used by the Roo Active Record system to allow new instances of your entities to get the necessary persistence information injected.

@Service

@Configurable

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService;



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile());

    }

}

Tag that works by using @Configurable on the service object: working-configurable

Manual bean lookup: not recommended

This approach is suitable only for interfacing with legacy code in special situations. It is nearly always preferable to create a singleton adapter class that Spring can autowire and the legacy code can call, but it is possible to directly ask the Spring application context for a bean.

To do this, you need a class to which Spring can give a reference to the ApplicationContext object:

@Component

public class ApplicationContextHolder implements ApplicationContextAware {

    private static ApplicationContext context;



    @Override

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context = applicationContext;   

    }



    public static ApplicationContext getContext() {

        return context;

    }

}

Then your legacy code can call getContext() and retrieve the beans it needs:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = ApplicationContextHolder.getContext().getBean(MileageFeeCalculator.class);

        return calc.mileageCharge(miles);

    }

}

Tag that works by manually looking up the service object in the Spring context: working-manual-lookup

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

1

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

|
show 6 more comments

up vote
46
down vote

If you are not coding a web application, make sure your class in which @Autowiring is done is a spring bean. Typically, spring container won't be aware of the class which we might think of as a spring bean. We have to tell the Spring container about our spring classes.

This can be achieved by configuring in appln-contxt or the better way is to annotate class as @Component and please do not create the annotated class using new operator.
Make sure you get it from Appln-context as below.

@Component

public class MyDemo {





    @Autowired

    private MyService  myService; 



    /**

     * @param args

     */

    public static void main(String args) {

        // TODO Auto-generated method stub

            System.out.println("test");

            ApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");

            System.out.println("ctx>>"+ctx);



            Customer c1=null;

            MyDemo myDemo=ctx.getBean(MyDemo.class);

            System.out.println(myDemo);

            myDemo.callService(ctx);





    }



    public void callService(ApplicationContext ctx) {

        // TODO Auto-generated method stub

        System.out.println("---callService---");

        System.out.println(myService);

        myService.callMydao();



    }



}

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

2

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

add a comment |

up vote
24
down vote

Actually, you should use either JVM managed Objects or Spring-managed Object to invoke methods.
from your above code in your controller class, you are creating a new object to call your service class which has an auto-wired object.

MileageFeeCalculator calc = new MileageFeeCalculator();

so it won't work that way.

The solution makes this MileageFeeCalculator as an auto-wired object in the Controller itself.

Change your Controller class like below.

@Controller

public class MileageFeeController {



    @Autowired

    MileageFeeCalculator calc;  



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

1

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

add a comment |

up vote
21
down vote

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

The root cause is, instead of using the auto-created bean maintained by the Spring IoC container (whose @Autowired field is indeed properly injected), I am newing my own instance of that bean type and using it. Of course this one's @Autowired field is null because Spring has no chance to inject it.

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

add a comment |

up vote
17
down vote

Your problem is new (object creation in java style)

MileageFeeCalculator calc = new MileageFeeCalculator();

With annotation @Service, @Component, @Configuration beans are created in the

application context of Spring when server is started. But when we create objects
using new operator the object is not registered in application context which is already created. For Example Employee.java class i have used.

Check this out:

public class ConfiguredTenantScopedBeanProcessor implements BeanFactoryPostProcessor {



@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    String name = "tenant";

    System.out.println("Bean factory post processor is initialized"); 

    beanFactory.registerScope("employee", new Employee());



    Assert.state(beanFactory instanceof BeanDefinitionRegistry,

            "BeanFactory was not a BeanDefinitionRegistry, so CustomScope cannot be used.");

    BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;



    for (String beanName : beanFactory.getBeanDefinitionNames()) {

        BeanDefinition definition = beanFactory.getBeanDefinition(beanName);

        if (name.equals(definition.getScope())) {

            BeanDefinitionHolder proxyHolder = ScopedProxyUtils.createScopedProxy(new BeanDefinitionHolder(definition, beanName), registry, true);

            registry.registerBeanDefinition(beanName, proxyHolder.getBeanDefinition());

        }

    }

}



}

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

add a comment |

up vote
8
down vote

It seems to be rare case but here is what happened to me:

We used @Inject instead of @Autowired which is javaee standard supported by Spring. Every places it worked fine and the beans injected correctly, instead of one place. The bean injection seems the same

@Inject

Calculator myCalculator

At last we found that the error was that we (actually, the Eclipse auto complete feature) imported com.opensymphony.xwork2.Inject instead of javax.inject.Inject !

So to summarize, make sure that your annotations (@Autowired, @Inject, @Service ,... ) have correct packages!

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

add a comment |

up vote
7
down vote

I'm new to Spring, but I discovered this working solution. Please tell me if it's a deprecable way.

I make Spring inject applicationContext in this bean:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.stereotype.Component;



@Component

public class SpringUtils {



    public static ApplicationContext ctx;



    /**

     * Make Spring inject the application context

     * and save it on a static variable,

     * so that it can be accessed from any point in the application. 

     */

    @Autowired

    private void setApplicationContext(ApplicationContext applicationContext) {

        ctx = applicationContext;       

    }

}

You can put this code also in the main application class if you want.

Other classes can use it like this:

MyBean myBean = (MyBean)SpringUtils.ctx.getBean(MyBean.class);

In this way any bean can be obtained by any object in the application (also intantiated with new) and in a static way.

answered May 14 '15 at 12:44

bluish

13.6k1693146

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

add a comment |

up vote
3
down vote

I think you have missed to instruct spring to scan classes with annotation.

You can use @ComponentScan("packageToScan") on the configuration class of your spring application to instruct spring to scan.

@Service, @Component etc annotations add meta description.

Spring only injects instances of those classes which are either created as bean or marked with annotation.

Classes marked with annotation need to be identified by spring before injecting, @ComponentScan instruct spring look for the classes marked with annotation. When Spring finds @Autowired it searches for the related bean, and injects the required instance.

Adding annotation only, does not fix or facilitate the dependency injection, Spring needs to know where to look for.

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

add a comment |

up vote
2
down vote

Another solution would be putting call:
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

To MileageFeeCalculator constructor like this:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- will be autowired when constructor is called



    public MileageFeeCalculator() {

        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

    }



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); 

    }

}

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

add a comment |

up vote
2
down vote

You can also fix this issue using @Service annotation on service class and passing the required bean classA as a parameter to the other beans classB constructor and annotate the constructor of classB with @Autowired. Sample snippet here :

@Service

public class ClassB {



    private ClassA classA;



    @Autowired

    public ClassB(ClassA classA) {

        this.classA = classA;

    }



    public void useClassAObjectHere(){

        classA.callMethodOnObjectA();

    }

}

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

1

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

add a comment |

up vote
2
down vote

UPDATE: Really smart people were quick to point on this answer, which explains the weirdness, described below

ORIGINAL ANSWER:

I don't know if it helps anyone, but I was stuck with the same problem even while doing things seemingly right. In my Main method, I have a code like this:

ApplicationContext context =

    new ClassPathXmlApplicationContext(new String {

        "common.xml",

        "token.xml",

        "pep-config.xml" });

    TokenInitializer ti = context.getBean(TokenInitializer.class);

and in a token.xml file I've had a line

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

I noticed that the package.path does no longer exist, so I've just dropped the line for good.

And after that, NPE started coming in. In a pep-config.xml I had just 2 beans:

<bean id="someAbac" class="com.pep.SomeAbac" init-method="init"/>

<bean id="settings" class="com.pep.Settings"/>

and SomeAbac class has a property declared as

@Autowired private Settings settings;

for some unknown reason, settings is null in init(), when <context:component-scan/> element is not present at all, but when it's present and has some bs as a basePackage, everything works well. This line now looks like this:

<context:component-scan base-package="some.shit"/>

and it works. May be someone can provide an explanation, but for me it's enough right now )

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

4

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

add a comment |

up vote
2
down vote

If this is happening in a test class, make sure you haven't forgotten to annotate the class.

For example, in Spring Boot:

@RunWith(SpringRunner.class)

@SpringBootTest

public class MyTests {

    ....

answered Apr 12 at 18:25

nobar

24.8k108497

add a comment |

protected by chrylis May 8 '14 at 15:21

Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

12 Answers
12

active

oldest

votes

12 Answers
12

active

oldest

votes

up vote
522
down vote

accepted

The field annotated @Autowired is null because Spring doesn't know about the copy of MileageFeeCalculator that you created with new and didn't know to autowire it.

Inject your beans

@Controller

public class MileageFeeController {



    @Autowired

    private MileageFeeCalculator calc;



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

If you need to create a new instance of your service object for different requests, you can still use injection by using the Spring bean scopes.

Tag that works by injecting the @MileageFeeCalculator service object: working-inject-bean

Use @Configurable

@Service

@Configurable

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService;



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile());

    }

}

Tag that works by using @Configurable on the service object: working-configurable

Manual bean lookup: not recommended

To do this, you need a class to which Spring can give a reference to the ApplicationContext object:

@Component

public class ApplicationContextHolder implements ApplicationContextAware {

    private static ApplicationContext context;



    @Override

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context = applicationContext;   

    }



    public static ApplicationContext getContext() {

        return context;

    }

}

Then your legacy code can call getContext() and retrieve the beans it needs:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = ApplicationContextHolder.getContext().getBean(MileageFeeCalculator.class);

        return calc.mileageCharge(miles);

    }

}

Tag that works by manually looking up the service object in the Spring context: working-manual-lookup

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

1

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

|
show 6 more comments

up vote
522
down vote

accepted

The field annotated @Autowired is null because Spring doesn't know about the copy of MileageFeeCalculator that you created with new and didn't know to autowire it.

Inject your beans

@Controller

public class MileageFeeController {



    @Autowired

    private MileageFeeCalculator calc;



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

If you need to create a new instance of your service object for different requests, you can still use injection by using the Spring bean scopes.

Tag that works by injecting the @MileageFeeCalculator service object: working-inject-bean

Use @Configurable

@Service

@Configurable

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService;



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile());

    }

}

Tag that works by using @Configurable on the service object: working-configurable

Manual bean lookup: not recommended

To do this, you need a class to which Spring can give a reference to the ApplicationContext object:

@Component

public class ApplicationContextHolder implements ApplicationContextAware {

    private static ApplicationContext context;



    @Override

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context = applicationContext;   

    }



    public static ApplicationContext getContext() {

        return context;

    }

}

Then your legacy code can call getContext() and retrieve the beans it needs:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = ApplicationContextHolder.getContext().getBean(MileageFeeCalculator.class);

        return calc.mileageCharge(miles);

    }

}

Tag that works by manually looking up the service object in the Spring context: working-manual-lookup

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

1

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

|
show 6 more comments

up vote
522
down vote

accepted

The field annotated @Autowired is null because Spring doesn't know about the copy of MileageFeeCalculator that you created with new and didn't know to autowire it.

Inject your beans

@Controller

public class MileageFeeController {



    @Autowired

    private MileageFeeCalculator calc;



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

If you need to create a new instance of your service object for different requests, you can still use injection by using the Spring bean scopes.

Tag that works by injecting the @MileageFeeCalculator service object: working-inject-bean

Use @Configurable

@Service

@Configurable

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService;



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile());

    }

}

Tag that works by using @Configurable on the service object: working-configurable

Manual bean lookup: not recommended

To do this, you need a class to which Spring can give a reference to the ApplicationContext object:

@Component

public class ApplicationContextHolder implements ApplicationContextAware {

    private static ApplicationContext context;



    @Override

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context = applicationContext;   

    }



    public static ApplicationContext getContext() {

        return context;

    }

}

Then your legacy code can call getContext() and retrieve the beans it needs:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = ApplicationContextHolder.getContext().getBean(MileageFeeCalculator.class);

        return calc.mileageCharge(miles);

    }

}

Tag that works by manually looking up the service object in the Spring context: working-manual-lookup

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

The field annotated @Autowired is null because Spring doesn't know about the copy of MileageFeeCalculator that you created with new and didn't know to autowire it.

Inject your beans

@Controller

public class MileageFeeController {



    @Autowired

    private MileageFeeCalculator calc;



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

If you need to create a new instance of your service object for different requests, you can still use injection by using the Spring bean scopes.

Tag that works by injecting the @MileageFeeCalculator service object: working-inject-bean

Use @Configurable

@Service

@Configurable

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService;



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile());

    }

}

Tag that works by using @Configurable on the service object: working-configurable

Manual bean lookup: not recommended

To do this, you need a class to which Spring can give a reference to the ApplicationContext object:

@Component

public class ApplicationContextHolder implements ApplicationContextAware {

    private static ApplicationContext context;



    @Override

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

        context = applicationContext;   

    }



    public static ApplicationContext getContext() {

        return context;

    }

}

Then your legacy code can call getContext() and retrieve the beans it needs:

@Controller

public class MileageFeeController {    

    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        MileageFeeCalculator calc = ApplicationContextHolder.getContext().getBean(MileageFeeCalculator.class);

        return calc.mileageCharge(miles);

    }

}

Tag that works by manually looking up the service object in the Spring context: working-manual-lookup

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

edited Feb 28 '16 at 19:40

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

answered Nov 11 '13 at 0:05

chrylis

49.8k1678114

1

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

1

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

|
show 6 more comments

1

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

1

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

The other thing to look at is making objects for beans in a @Configuration bean, where the method to make an instance of a particular bean class is annotated with @Bean.
– Donal Fellows
Nov 11 '13 at 0:12

@DonalFellows I'm not entirely sure what you're talking about ("making" is ambiguous). Are you talking about a problem with multiple calls to @Bean methods when using Spring Proxy AOP?
– chrylis
Nov 11 '13 at 0:16

Hi there, I am running into a similar issue, however when I use your first suggestion, my application thinks "calc" is null when calling the "mileageFee" method. It's as if it never initializes the @Autowired MileageFeeCalculator calc. Any thoughts?
– Theo
Jul 14 '14 at 22:00

I think you should add an entry at the top of your answer that explains that retrieving the first bean, the root from which you do everything, should be done through the ApplicationContext. Some users (for which I've closed as duplicates) don't understand this.
– Sotirios Delimanolis
Oct 18 '14 at 1:39

@SotiriosDelimanolis Please explain the issue; I'm not sure exactly what point you're making.
– chrylis
Oct 18 '14 at 2:40

|
show 6 more comments

up vote
46
down vote

@Component

public class MyDemo {





    @Autowired

    private MyService  myService; 



    /**

     * @param args

     */

    public static void main(String args) {

        // TODO Auto-generated method stub

            System.out.println("test");

            ApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");

            System.out.println("ctx>>"+ctx);



            Customer c1=null;

            MyDemo myDemo=ctx.getBean(MyDemo.class);

            System.out.println(myDemo);

            myDemo.callService(ctx);





    }



    public void callService(ApplicationContext ctx) {

        // TODO Auto-generated method stub

        System.out.println("---callService---");

        System.out.println(myService);

        myService.callMydao();



    }



}

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

2

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

add a comment |

up vote
46
down vote

@Component

public class MyDemo {





    @Autowired

    private MyService  myService; 



    /**

     * @param args

     */

    public static void main(String args) {

        // TODO Auto-generated method stub

            System.out.println("test");

            ApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");

            System.out.println("ctx>>"+ctx);



            Customer c1=null;

            MyDemo myDemo=ctx.getBean(MyDemo.class);

            System.out.println(myDemo);

            myDemo.callService(ctx);





    }



    public void callService(ApplicationContext ctx) {

        // TODO Auto-generated method stub

        System.out.println("---callService---");

        System.out.println(myService);

        myService.callMydao();



    }



}

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

2

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

add a comment |

up vote
46
down vote

@Component

public class MyDemo {





    @Autowired

    private MyService  myService; 



    /**

     * @param args

     */

    public static void main(String args) {

        // TODO Auto-generated method stub

            System.out.println("test");

            ApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");

            System.out.println("ctx>>"+ctx);



            Customer c1=null;

            MyDemo myDemo=ctx.getBean(MyDemo.class);

            System.out.println(myDemo);

            myDemo.callService(ctx);





    }



    public void callService(ApplicationContext ctx) {

        // TODO Auto-generated method stub

        System.out.println("---callService---");

        System.out.println(myService);

        myService.callMydao();



    }



}

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

@Component

public class MyDemo {





    @Autowired

    private MyService  myService; 



    /**

     * @param args

     */

    public static void main(String args) {

        // TODO Auto-generated method stub

            System.out.println("test");

            ApplicationContext ctx=new ClassPathXmlApplicationContext("spring.xml");

            System.out.println("ctx>>"+ctx);



            Customer c1=null;

            MyDemo myDemo=ctx.getBean(MyDemo.class);

            System.out.println(myDemo);

            myDemo.callService(ctx);





    }



    public void callService(ApplicationContext ctx) {

        // TODO Auto-generated method stub

        System.out.println("---callService---");

        System.out.println(myService);

        myService.callMydao();



    }



}

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

edited Jan 2 '16 at 15:01

Andrew Morton

15k53049

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

answered Apr 22 '14 at 6:47

Shirish Coolkarni

56942

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

2

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

add a comment |

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

2

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

hi , I gone through your solution, that's correct . And Here I would like to know " Why we don't create instance of annotated class using new operator, may I know the reason behind that.
– Ashish
Dec 29 '14 at 11:30

if u create the object using new, u will be handling the life cycle of the bean which contradicts the concept of IOC. We need to ask the container to do it, which does it in a better way
– Shirish Coolkarni
Aug 20 '15 at 3:04

add a comment |

up vote
24
down vote

MileageFeeCalculator calc = new MileageFeeCalculator();

so it won't work that way.

The solution makes this MileageFeeCalculator as an auto-wired object in the Controller itself.

Change your Controller class like below.

@Controller

public class MileageFeeController {



    @Autowired

    MileageFeeCalculator calc;  



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

1

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

add a comment |

up vote
24
down vote

MileageFeeCalculator calc = new MileageFeeCalculator();

so it won't work that way.

The solution makes this MileageFeeCalculator as an auto-wired object in the Controller itself.

Change your Controller class like below.

@Controller

public class MileageFeeController {



    @Autowired

    MileageFeeCalculator calc;  



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

1

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

add a comment |

up vote
24
down vote

MileageFeeCalculator calc = new MileageFeeCalculator();

so it won't work that way.

The solution makes this MileageFeeCalculator as an auto-wired object in the Controller itself.

Change your Controller class like below.

@Controller

public class MileageFeeController {



    @Autowired

    MileageFeeCalculator calc;  



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

MileageFeeCalculator calc = new MileageFeeCalculator();

so it won't work that way.

The solution makes this MileageFeeCalculator as an auto-wired object in the Controller itself.

Change your Controller class like below.

@Controller

public class MileageFeeController {



    @Autowired

    MileageFeeCalculator calc;  



    @RequestMapping("/mileage/{miles}")

    @ResponseBody

    public float mileageFee(@PathVariable int miles) {

        return calc.mileageCharge(miles);

    }

}

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

edited Jul 26 at 19:21

KIN

40749

edited Jul 26 at 19:21

KIN

40749

edited Jul 26 at 19:21

KIN

40749

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

answered Jul 26 '16 at 9:25

Ravi Durairaj

47134

1

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

add a comment |

1

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

This is the answer. Because you're instantiating a new MilageFeeCalculator on your own, Spring isn't involved in the instantiation, so Spring spring has no knowledge the object exists. Thus, it can't do anything to it, like inject dependencies.
– Robert Greathouse
Sep 19 '17 at 17:27

add a comment |

up vote
21
down vote

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

add a comment |

up vote
21
down vote

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

add a comment |

up vote
21
down vote

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

I once encountered the same issue when I was not quite used to the life in the IoC world. The @Autowired field of one of my beans is null at runtime.

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

edited May 3 '16 at 8:46

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

answered Nov 12 '15 at 13:41

smwikipedia

20.5k61208363

add a comment |

up vote
17
down vote

Your problem is new (object creation in java style)

MileageFeeCalculator calc = new MileageFeeCalculator();

Check this out:

public class ConfiguredTenantScopedBeanProcessor implements BeanFactoryPostProcessor {



@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    String name = "tenant";

    System.out.println("Bean factory post processor is initialized"); 

    beanFactory.registerScope("employee", new Employee());



    Assert.state(beanFactory instanceof BeanDefinitionRegistry,

            "BeanFactory was not a BeanDefinitionRegistry, so CustomScope cannot be used.");

    BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;



    for (String beanName : beanFactory.getBeanDefinitionNames()) {

        BeanDefinition definition = beanFactory.getBeanDefinition(beanName);

        if (name.equals(definition.getScope())) {

            BeanDefinitionHolder proxyHolder = ScopedProxyUtils.createScopedProxy(new BeanDefinitionHolder(definition, beanName), registry, true);

            registry.registerBeanDefinition(beanName, proxyHolder.getBeanDefinition());

        }

    }

}



}

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

add a comment |

up vote
17
down vote

Your problem is new (object creation in java style)

MileageFeeCalculator calc = new MileageFeeCalculator();

Check this out:

public class ConfiguredTenantScopedBeanProcessor implements BeanFactoryPostProcessor {



@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    String name = "tenant";

    System.out.println("Bean factory post processor is initialized"); 

    beanFactory.registerScope("employee", new Employee());



    Assert.state(beanFactory instanceof BeanDefinitionRegistry,

            "BeanFactory was not a BeanDefinitionRegistry, so CustomScope cannot be used.");

    BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;



    for (String beanName : beanFactory.getBeanDefinitionNames()) {

        BeanDefinition definition = beanFactory.getBeanDefinition(beanName);

        if (name.equals(definition.getScope())) {

            BeanDefinitionHolder proxyHolder = ScopedProxyUtils.createScopedProxy(new BeanDefinitionHolder(definition, beanName), registry, true);

            registry.registerBeanDefinition(beanName, proxyHolder.getBeanDefinition());

        }

    }

}



}

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

add a comment |

up vote
17
down vote

Your problem is new (object creation in java style)

MileageFeeCalculator calc = new MileageFeeCalculator();

Check this out:

public class ConfiguredTenantScopedBeanProcessor implements BeanFactoryPostProcessor {



@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    String name = "tenant";

    System.out.println("Bean factory post processor is initialized"); 

    beanFactory.registerScope("employee", new Employee());



    Assert.state(beanFactory instanceof BeanDefinitionRegistry,

            "BeanFactory was not a BeanDefinitionRegistry, so CustomScope cannot be used.");

    BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;



    for (String beanName : beanFactory.getBeanDefinitionNames()) {

        BeanDefinition definition = beanFactory.getBeanDefinition(beanName);

        if (name.equals(definition.getScope())) {

            BeanDefinitionHolder proxyHolder = ScopedProxyUtils.createScopedProxy(new BeanDefinitionHolder(definition, beanName), registry, true);

            registry.registerBeanDefinition(beanName, proxyHolder.getBeanDefinition());

        }

    }

}



}

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

Your problem is new (object creation in java style)

MileageFeeCalculator calc = new MileageFeeCalculator();

Check this out:

public class ConfiguredTenantScopedBeanProcessor implements BeanFactoryPostProcessor {



@Override

public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    String name = "tenant";

    System.out.println("Bean factory post processor is initialized"); 

    beanFactory.registerScope("employee", new Employee());



    Assert.state(beanFactory instanceof BeanDefinitionRegistry,

            "BeanFactory was not a BeanDefinitionRegistry, so CustomScope cannot be used.");

    BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;



    for (String beanName : beanFactory.getBeanDefinitionNames()) {

        BeanDefinition definition = beanFactory.getBeanDefinition(beanName);

        if (name.equals(definition.getScope())) {

            BeanDefinitionHolder proxyHolder = ScopedProxyUtils.createScopedProxy(new BeanDefinitionHolder(definition, beanName), registry, true);

            registry.registerBeanDefinition(beanName, proxyHolder.getBeanDefinition());

        }

    }

}



}

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

edited Apr 12 at 10:43

Ahmed Ashour

3,470102442

answered Oct 8 '15 at 9:17

Deepak

1,0051218

answered Oct 8 '15 at 9:17

Deepak

1,0051218

answered Oct 8 '15 at 9:17

Deepak

1,0051218

add a comment |

up vote
8
down vote

It seems to be rare case but here is what happened to me:

@Inject

Calculator myCalculator

At last we found that the error was that we (actually, the Eclipse auto complete feature) imported com.opensymphony.xwork2.Inject instead of javax.inject.Inject !

So to summarize, make sure that your annotations (@Autowired, @Inject, @Service ,... ) have correct packages!

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

add a comment |

up vote
8
down vote

It seems to be rare case but here is what happened to me:

@Inject

Calculator myCalculator

At last we found that the error was that we (actually, the Eclipse auto complete feature) imported com.opensymphony.xwork2.Inject instead of javax.inject.Inject !

So to summarize, make sure that your annotations (@Autowired, @Inject, @Service ,... ) have correct packages!

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

add a comment |

up vote
8
down vote

It seems to be rare case but here is what happened to me:

@Inject

Calculator myCalculator

At last we found that the error was that we (actually, the Eclipse auto complete feature) imported com.opensymphony.xwork2.Inject instead of javax.inject.Inject !

So to summarize, make sure that your annotations (@Autowired, @Inject, @Service ,... ) have correct packages!

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

It seems to be rare case but here is what happened to me:

@Inject

Calculator myCalculator

At last we found that the error was that we (actually, the Eclipse auto complete feature) imported com.opensymphony.xwork2.Inject instead of javax.inject.Inject !

So to summarize, make sure that your annotations (@Autowired, @Inject, @Service ,... ) have correct packages!

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

edited Apr 20 at 13:07

TwiN

1,6911619

edited Apr 20 at 13:07

TwiN

1,6911619

edited Apr 20 at 13:07

TwiN

1,6911619

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

answered Jun 11 '16 at 15:15

Alireza Fattahi

20.2k86589

add a comment |

up vote
7
down vote

I'm new to Spring, but I discovered this working solution. Please tell me if it's a deprecable way.

I make Spring inject applicationContext in this bean:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.stereotype.Component;



@Component

public class SpringUtils {



    public static ApplicationContext ctx;



    /**

     * Make Spring inject the application context

     * and save it on a static variable,

     * so that it can be accessed from any point in the application. 

     */

    @Autowired

    private void setApplicationContext(ApplicationContext applicationContext) {

        ctx = applicationContext;       

    }

}

You can put this code also in the main application class if you want.

Other classes can use it like this:

MyBean myBean = (MyBean)SpringUtils.ctx.getBean(MyBean.class);

In this way any bean can be obtained by any object in the application (also intantiated with new) and in a static way.

answered May 14 '15 at 12:44

bluish

13.6k1693146

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

add a comment |

up vote
7
down vote

I'm new to Spring, but I discovered this working solution. Please tell me if it's a deprecable way.

I make Spring inject applicationContext in this bean:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.stereotype.Component;



@Component

public class SpringUtils {



    public static ApplicationContext ctx;



    /**

     * Make Spring inject the application context

     * and save it on a static variable,

     * so that it can be accessed from any point in the application. 

     */

    @Autowired

    private void setApplicationContext(ApplicationContext applicationContext) {

        ctx = applicationContext;       

    }

}

You can put this code also in the main application class if you want.

Other classes can use it like this:

MyBean myBean = (MyBean)SpringUtils.ctx.getBean(MyBean.class);

In this way any bean can be obtained by any object in the application (also intantiated with new) and in a static way.

answered May 14 '15 at 12:44

bluish

13.6k1693146

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

add a comment |

up vote
7
down vote

I'm new to Spring, but I discovered this working solution. Please tell me if it's a deprecable way.

I make Spring inject applicationContext in this bean:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.stereotype.Component;



@Component

public class SpringUtils {



    public static ApplicationContext ctx;



    /**

     * Make Spring inject the application context

     * and save it on a static variable,

     * so that it can be accessed from any point in the application. 

     */

    @Autowired

    private void setApplicationContext(ApplicationContext applicationContext) {

        ctx = applicationContext;       

    }

}

You can put this code also in the main application class if you want.

Other classes can use it like this:

MyBean myBean = (MyBean)SpringUtils.ctx.getBean(MyBean.class);

In this way any bean can be obtained by any object in the application (also intantiated with new) and in a static way.

answered May 14 '15 at 12:44

bluish

13.6k1693146

I'm new to Spring, but I discovered this working solution. Please tell me if it's a deprecable way.

I make Spring inject applicationContext in this bean:

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.ApplicationContext;

import org.springframework.stereotype.Component;



@Component

public class SpringUtils {



    public static ApplicationContext ctx;



    /**

     * Make Spring inject the application context

     * and save it on a static variable,

     * so that it can be accessed from any point in the application. 

     */

    @Autowired

    private void setApplicationContext(ApplicationContext applicationContext) {

        ctx = applicationContext;       

    }

}

You can put this code also in the main application class if you want.

Other classes can use it like this:

MyBean myBean = (MyBean)SpringUtils.ctx.getBean(MyBean.class);

In this way any bean can be obtained by any object in the application (also intantiated with new) and in a static way.

answered May 14 '15 at 12:44

bluish

13.6k1693146

answered May 14 '15 at 12:44

bluish

13.6k1693146

answered May 14 '15 at 12:44

bluish

13.6k1693146

answered May 14 '15 at 12:44

bluish

13.6k1693146

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

add a comment |

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

This pattern is necessary to make Spring beans accessible to legacy code but should be avoided in new code.
– chrylis
May 14 '15 at 13:06

add a comment |

up vote
3
down vote

I think you have missed to instruct spring to scan classes with annotation.

You can use @ComponentScan("packageToScan") on the configuration class of your spring application to instruct spring to scan.

@Service, @Component etc annotations add meta description.

Spring only injects instances of those classes which are either created as bean or marked with annotation.

Adding annotation only, does not fix or facilitate the dependency injection, Spring needs to know where to look for.

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

add a comment |

up vote
3
down vote

I think you have missed to instruct spring to scan classes with annotation.

You can use @ComponentScan("packageToScan") on the configuration class of your spring application to instruct spring to scan.

@Service, @Component etc annotations add meta description.

Spring only injects instances of those classes which are either created as bean or marked with annotation.

Adding annotation only, does not fix or facilitate the dependency injection, Spring needs to know where to look for.

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

add a comment |

up vote
3
down vote

I think you have missed to instruct spring to scan classes with annotation.

You can use @ComponentScan("packageToScan") on the configuration class of your spring application to instruct spring to scan.

@Service, @Component etc annotations add meta description.

Spring only injects instances of those classes which are either created as bean or marked with annotation.

Adding annotation only, does not fix or facilitate the dependency injection, Spring needs to know where to look for.

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

I think you have missed to instruct spring to scan classes with annotation.

You can use @ComponentScan("packageToScan") on the configuration class of your spring application to instruct spring to scan.

@Service, @Component etc annotations add meta description.

Spring only injects instances of those classes which are either created as bean or marked with annotation.

Adding annotation only, does not fix or facilitate the dependency injection, Spring needs to know where to look for.

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

edited Jan 10 '17 at 19:34

Newd

2,04421330

edited Jan 10 '17 at 19:34

Newd

2,04421330

edited Jan 10 '17 at 19:34

Newd

2,04421330

answered Jan 10 '17 at 18:00

msucil

1811110

answered Jan 10 '17 at 18:00

msucil

1811110

answered Jan 10 '17 at 18:00

msucil

1811110

add a comment |

up vote
2
down vote

Another solution would be putting call:
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

To MileageFeeCalculator constructor like this:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- will be autowired when constructor is called



    public MileageFeeCalculator() {

        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

    }



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); 

    }

}

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

add a comment |

up vote
2
down vote

Another solution would be putting call:
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

To MileageFeeCalculator constructor like this:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- will be autowired when constructor is called



    public MileageFeeCalculator() {

        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

    }



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); 

    }

}

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

add a comment |

up vote
2
down vote

Another solution would be putting call:
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

To MileageFeeCalculator constructor like this:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- will be autowired when constructor is called



    public MileageFeeCalculator() {

        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

    }



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); 

    }

}

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

Another solution would be putting call:
SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

To MileageFeeCalculator constructor like this:

@Service

public class MileageFeeCalculator {



    @Autowired

    private MileageRateService rateService; // <--- will be autowired when constructor is called



    public MileageFeeCalculator() {

        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this)

    }



    public float mileageCharge(final int miles) {

        return (miles * rateService.ratePerMile()); 

    }

}

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

edited Apr 21 '15 at 11:42

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

answered Apr 21 '15 at 11:35

Ondrej Bozek

5,98933760

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

add a comment |

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

This uses unsafe publication.
– chrylis
Apr 21 '15 at 12:41

add a comment |

up vote
2
down vote

@Service

public class ClassB {



    private ClassA classA;



    @Autowired

    public ClassB(ClassA classA) {

        this.classA = classA;

    }



    public void useClassAObjectHere(){

        classA.callMethodOnObjectA();

    }

}

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

1

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

add a comment |

up vote
2
down vote

@Service

public class ClassB {



    private ClassA classA;



    @Autowired

    public ClassB(ClassA classA) {

        this.classA = classA;

    }



    public void useClassAObjectHere(){

        classA.callMethodOnObjectA();

    }

}

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

1

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

add a comment |

up vote
2
down vote

@Service

public class ClassB {



    private ClassA classA;



    @Autowired

    public ClassB(ClassA classA) {

        this.classA = classA;

    }



    public void useClassAObjectHere(){

        classA.callMethodOnObjectA();

    }

}

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

@Service

public class ClassB {



    private ClassA classA;



    @Autowired

    public ClassB(ClassA classA) {

        this.classA = classA;

    }



    public void useClassAObjectHere(){

        classA.callMethodOnObjectA();

    }

}

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

edited Oct 13 '16 at 18:56

answered Oct 13 '16 at 18:41

apandey846

832919

answered Oct 13 '16 at 18:41

apandey846

832919

answered Oct 13 '16 at 18:41

apandey846

832919

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

1

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

add a comment |

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

1

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

this worked for me bu t can you please elaborate on how this is solving the issue ?
– CruelEngine
Mar 5 at 12:58

@CruelEngine, look this is constructor injection (where you explicitly setting an object) instead of just using field injection (this is mostly done by spring configuration mostly). So if you are creating a object of ClassB using "new" operator is some other scope then that would not be visible or autowired set for ClassA. Hence, while calling classB.useClassAObjectHere() would throw NPE as classA object was not autowired if you just declare field Injection. Read chrylis is trying to explain same. And this why constructor injection is recommended over field injection. Does it make sense now ?
– apandey846
Apr 11 at 8:45

now i get it . thanks :)
– CruelEngine
Apr 11 at 12:28

add a comment |

up vote
2
down vote

UPDATE: Really smart people were quick to point on this answer, which explains the weirdness, described below

ORIGINAL ANSWER:

I don't know if it helps anyone, but I was stuck with the same problem even while doing things seemingly right. In my Main method, I have a code like this:

ApplicationContext context =

    new ClassPathXmlApplicationContext(new String {

        "common.xml",

        "token.xml",

        "pep-config.xml" });

    TokenInitializer ti = context.getBean(TokenInitializer.class);

and in a token.xml file I've had a line

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

I noticed that the package.path does no longer exist, so I've just dropped the line for good.

And after that, NPE started coming in. In a pep-config.xml I had just 2 beans:

<bean id="someAbac" class="com.pep.SomeAbac" init-method="init"/>

<bean id="settings" class="com.pep.Settings"/>

and SomeAbac class has a property declared as

@Autowired private Settings settings;

<context:component-scan base-package="some.shit"/>

and it works. May be someone can provide an explanation, but for me it's enough right now )

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

4

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

add a comment |

up vote
2
down vote

UPDATE: Really smart people were quick to point on this answer, which explains the weirdness, described below

ORIGINAL ANSWER:

I don't know if it helps anyone, but I was stuck with the same problem even while doing things seemingly right. In my Main method, I have a code like this:

ApplicationContext context =

    new ClassPathXmlApplicationContext(new String {

        "common.xml",

        "token.xml",

        "pep-config.xml" });

    TokenInitializer ti = context.getBean(TokenInitializer.class);

and in a token.xml file I've had a line

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

I noticed that the package.path does no longer exist, so I've just dropped the line for good.

And after that, NPE started coming in. In a pep-config.xml I had just 2 beans:

<bean id="someAbac" class="com.pep.SomeAbac" init-method="init"/>

<bean id="settings" class="com.pep.Settings"/>

and SomeAbac class has a property declared as

@Autowired private Settings settings;

<context:component-scan base-package="some.shit"/>

and it works. May be someone can provide an explanation, but for me it's enough right now )

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

4

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

add a comment |

up vote
2
down vote

UPDATE: Really smart people were quick to point on this answer, which explains the weirdness, described below

ORIGINAL ANSWER:

I don't know if it helps anyone, but I was stuck with the same problem even while doing things seemingly right. In my Main method, I have a code like this:

ApplicationContext context =

    new ClassPathXmlApplicationContext(new String {

        "common.xml",

        "token.xml",

        "pep-config.xml" });

    TokenInitializer ti = context.getBean(TokenInitializer.class);

and in a token.xml file I've had a line

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

I noticed that the package.path does no longer exist, so I've just dropped the line for good.

And after that, NPE started coming in. In a pep-config.xml I had just 2 beans:

<bean id="someAbac" class="com.pep.SomeAbac" init-method="init"/>

<bean id="settings" class="com.pep.Settings"/>

and SomeAbac class has a property declared as

@Autowired private Settings settings;

<context:component-scan base-package="some.shit"/>

and it works. May be someone can provide an explanation, but for me it's enough right now )

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

UPDATE: Really smart people were quick to point on this answer, which explains the weirdness, described below

ORIGINAL ANSWER:

I don't know if it helps anyone, but I was stuck with the same problem even while doing things seemingly right. In my Main method, I have a code like this:

ApplicationContext context =

    new ClassPathXmlApplicationContext(new String {

        "common.xml",

        "token.xml",

        "pep-config.xml" });

    TokenInitializer ti = context.getBean(TokenInitializer.class);

and in a token.xml file I've had a line

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

I noticed that the package.path does no longer exist, so I've just dropped the line for good.

And after that, NPE started coming in. In a pep-config.xml I had just 2 beans:

<bean id="someAbac" class="com.pep.SomeAbac" init-method="init"/>

<bean id="settings" class="com.pep.Settings"/>

and SomeAbac class has a property declared as

@Autowired private Settings settings;

<context:component-scan base-package="some.shit"/>

and it works. May be someone can provide an explanation, but for me it's enough right now )

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

edited Apr 12 at 10:42

Ahmed Ashour

3,470102442

answered Oct 12 '17 at 4:43

62mkv

505517

answered Oct 12 '17 at 4:43

62mkv

505517

answered Oct 12 '17 at 4:43

62mkv

505517

4

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

add a comment |

4

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

That answer is the explanation. <context:component-scan/> implicitly enables <context:annotation-config/> necessary for the @Autowired to work.
– ForNeVeR
Oct 12 '17 at 4:55

add a comment |

up vote
2
down vote

If this is happening in a test class, make sure you haven't forgotten to annotate the class.

For example, in Spring Boot:

@RunWith(SpringRunner.class)

@SpringBootTest

public class MyTests {

    ....

answered Apr 12 at 18:25

nobar

24.8k108497

add a comment |

up vote
2
down vote

If this is happening in a test class, make sure you haven't forgotten to annotate the class.

For example, in Spring Boot:

@RunWith(SpringRunner.class)

@SpringBootTest

public class MyTests {

    ....

answered Apr 12 at 18:25

nobar

24.8k108497

add a comment |

up vote
2
down vote

If this is happening in a test class, make sure you haven't forgotten to annotate the class.

For example, in Spring Boot:

@RunWith(SpringRunner.class)

@SpringBootTest

public class MyTests {

    ....

answered Apr 12 at 18:25

nobar

24.8k108497

If this is happening in a test class, make sure you haven't forgotten to annotate the class.

For example, in Spring Boot:

@RunWith(SpringRunner.class)

@SpringBootTest

public class MyTests {

    ....

answered Apr 12 at 18:25

nobar

24.8k108497

answered Apr 12 at 18:25

nobar

24.8k108497

answered Apr 12 at 18:25

nobar

24.8k108497

answered Apr 12 at 18:25

nobar

24.8k108497

add a comment |

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