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Cannot getBean after adding #Component above Class

I cannot get the bean by adding #Component on it.
I have created a class as below for getting bean in cases where instances are not injected by #autowired.
#Component
public class SpringApplicationContext implements ApplicationContextAware{
private static ApplicationContext CONTEXT;
public static Object getBean(String beanName) {
return CONTEXT.getBean(beanName);
}
#Override
public void setApplicationContext(ApplicationContext context)
throws BeansException {
CONTEXT = context;
}
}
Then I created a AppProperties class for reading the decrypt token from application.properties.
#Component
public class AppProperties {
#Autowired
private Environment env;
public String getTokenSecret() {
return env.getProperty("tokenSecret");
}
}
Then, I try to get the AppProperties instance as bean like this, which SecurityConstants.getTokenSecret() are used as parameter by manually inject in another method like this:
public class SecurityConstants {
...
public static String getTokenSecret() {
//Fail to get bean in this line
AppProperties appProperties = (AppProperties)SpringApplicationContext.getBean("AppProperties");
return appProperties.getTokenSecret();
}
}
but fail with below exception:
org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'AppProperties' available
After that, I add getAppProperties() with #Bean to make it register as a bean and it worked.
#SpringBootApplication
public class RegAppApplication {
public static void main(String[] args) {
SpringApplication.run(RegAppApplication.class, args);
}
#Bean(name="AppProperties")
public AppProperties getAppProperties() {
return new AppProperties();
}
}
The question is:
Why SpringApplicationContext is run on application start and AppProperties does not?
Why cannot get AppProperties as bean? Isn't adding #Component above the class will make it a component scan target, thus being treated as a bean?
How adding getAppProperties() with #Bean making it different with adding #Component above the class?
Thank you.

Unresolved dependency in UnitTesting Spring Boot

I getting the following error when trying to write a unit test for CircuitBreaker code example.
org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name
'com.foosball.team.Service.TeamServiceUnitTest': Unsatisfied
dependency expressed through field 'registry'; nested exception is
org.springframework.beans.factory.NoSuchBeanDefinitionException: No
qualifying bean of type
'io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry'
available: expected at least 1 bean which qualifies as autowire
candidate. Dependency annotations:
{#org.springframework.beans.factory.annotation.Autowired(required=true)}
TeamService:
#Service
public class TeamService {
#Autowired
private ITeamRepository teamRepository;
#Autowired
private PlayerClient playerClient;
Logger logger = LoggerFactory.getLogger(TeamService.class);
.
.
.
TeamServiceUnitTest:
#SpringBootTest(classes = {
TeamService.class
})
#RunWith(SpringRunner.class)
#DirtiesContext
public class TeamServiceUnitTest extends AbstractCircuitBreakerTest {
#MockBean
private ITeamRepository teamRepository;
#MockBean
private PlayerClient playerClient;
#Autowired
private TeamService service;
private TeamEntity teamEntity;
private Logger logger = LoggerFactory.getLogger(TeamServiceUnitTest.class);
#Before
public void setUp(){
teamEntity = new TeamEntity();
teamEntity.setId(1L);
teamEntity.setPlayerOne("One");
teamEntity.setPlayerTwo("Two");
teamEntity.setPlayerThree("Three");
teamEntity.setPlayerFour("Four");
}
#Test
#DisplayName("when Player Client Fails 11 Times Then CircuitBreaker Should Be In OPEN State")
public void whenPlayerClientFailsElevenTimesThenCircuitBreakerShouldBeInOPENState(){
//Given
when(teamRepository.findAll()).thenReturn(new ArrayList<>());
when(playerClient.get(Mockito.anyString())).thenThrow(new RuntimeException());
//When
for(int i=0; i<11; i++){
try {
service.addTeam(teamEntity);
} catch (Exception ignore) {
logger.info(ignore.getClass().getName());
}
}
//Then
checkHealthStatus(BACKEND_B, CircuitBreaker.State.OPEN);
}
}
Ref Class:
public class AbstractCircuitBreakerTest {
protected static final String BACKEND_A = "backendA";
protected static final String BACKEND_B = "playerClientCircuitBreaker";
#Autowired
protected CircuitBreakerRegistry registry;
#Before
public void setup(){
transitionToClosedState(BACKEND_A);
transitionToClosedState(BACKEND_B);
}
protected void checkHealthStatus(String circuitBreakerName, CircuitBreaker.State state) {
CircuitBreaker circuitBreaker = registry.circuitBreaker(circuitBreakerName);
assertThat(circuitBreaker.getState()).isEqualTo(state);
}
protected void transitionToOpenState(String circuitBreakerName) {
CircuitBreaker circuitBreaker = registry.circuitBreaker(circuitBreakerName);
if(!circuitBreaker.getState().equals(CircuitBreaker.State.OPEN)){
circuitBreaker.transitionToOpenState();
}
}
protected void transitionToClosedState(String circuitBreakerName) {
CircuitBreaker circuitBreaker = registry.circuitBreaker(circuitBreakerName);
if(!circuitBreaker.getState().equals(CircuitBreaker.State.CLOSED)){
circuitBreaker.transitionToClosedState();
}
}
}
Ref Project: https://github.com/resilience4j/resilience4j-spring-boot2-demo
Proposed Soln Discussion: https://github.com/resilience4j/resilience4j-spring-boot2-demo/issues/33
Proposed Soln Project: https://github.com/shah-smit/resilience4j-spring-boot2-demo-maven

Looks like CircuitBreakerRegistry you're trying to autowire in you test is a factory class, not a bean. Instead of
#Autowired
protected CircuitBreakerRegistry registry;
Try:
protected CircuitBreakerRegistry registry = CircuitBreakerRegistry.ofDefaults()

Here's an answer about not working tests.
Few things here:
1. Using CircuitBreakerRegistry.ofDefaults() creates new instance of object each time so this way the CircuitBreakerRegistry objects you're using in AbstractCircuitBreakerTest and HomeService are different instances. You should probably go back to #Autowired annotation but first you need to define bean of CircuitBreakerRegistry like this:
public class CircuitBreakerConfiguration {
#Bean
public CircuitBreakerRegistry circuitBreakerRegistry() {
return CircuitBreakerRegistry.ofDefaults();
}
}
You're using #RunWith(SpringRunner.class) but it's just Junit annotation and it does not initialize Spring Context in your test. You're autowiring a bean in your test so you need Spring Context. For this add also #SpringBootTest annotation.
You're expecting the registry BACKEND_A state to change to OPEN after 11 calls of service.getGreeting() method but I cannot see any usage of transitionToOpenState method.

coundn't get bean when running a jar packed from a springboot project

I can run my springboot project in IDEA nicely but when packed it to a jar and run with the java command, just got the java.lang.NullPointerException when getting a bean from spring context.
the first class which just got errors:
#Service
public class MdspiImpl extends CThostFtdcMdSpi {
public MdspiImpl(CThostFtdcMdApi mdapi) {
m_mdapi = mdapi;
logger.info("MdspiImpl is creating...");
***mdr = SpringContextUtil.getBean("marketDataRobot");//this is the error code***
}
}
the second class:
#Service
public class MarketDataRobot {
}
the SpringContextUtil class:
#Component("SpringContextUtil")
public class SpringContextUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext;
public static <T> T getBean(String name) {
return (T) applicationContext.getBean(name);
}
}
the gradle file:
jar {
baseName = 'programmingTrading'
version = '0.1.0'
manifest {
attributes 'Main-Class': 'com.blackHole.programmingTrading'
}
}
the running exception:
WARN main[AbstractApplicationContext.java:557 Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mdspiImpl' defined in URL [jar:file:/E:/workspace/simuPrd/programmingTrading-0.0.1-SNAPSHOT.jar!/BOOT-INF/classes!/com/blackHole/programmingTrading/infrastructure/MdspiImpl.class]: Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.blackHole.programmingTrading.infrastructure.MdspiImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException]
[com.blackHole.programmingTrading.infrastructure.MdspiImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:184)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:117)
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:300)
... 27 common frames omitted
Caused by: java.lang.NullPointerException: null
at com.blackHole.programmingTrading.SpringContextUtil.getBean(SpringContextUtil.java:35)
at com.blackHole.programmingTrading.infrastructure.MdspiImpl.<init>(MdspiImpl.java:46)
It also stem from another problem: #Autowired annotation doesn't work...
when using like this:
#Component
public class Scu{
}
in another class:
#Autowired
private Scu scu;
logger.info(String.format("MdspiImpl is creating...[%s]", scu.toString()));
will get a java.lang.NullPointerException: null
spring-boot configuration like this:
#SpringBootApplication
public class ProgrammingTrading {
public static void main(String[] args) {
SpringApplication.run(ProgrammingTrading.class, args);
}
}
that is part of reasons of using SpringContextUtil to get the bean...
thanks a lot!

SpringContextUtil shouldn't be a accessed statically like you are doing... Since you define it as a #Component do the following;
#Service
public class MdspiImpl extends CThostFtdcMdSpi {
#Autowired
private SpringContextUtil springContextUtil;
public MdspiImpl(CThostFtdcMdApi mdapi) {
m_mdapi = mdapi;
logger.info("MdspiImpl is creating...");
***mdr = springContextUtil.getBean("marketDataRobot");
}
}
Due to SpringContextUtil not being injected via Spring, but simply accessed statically, the applicationContext inside of it is ignored and is null in your case.
Also remove the static modifier;
#Component
public class SpringContextUtil implements ApplicationContextAware {
private ApplicationContext applicationContext;
// include getter/setter for applicationContext as well
public <T> T getBean(String name) {
return (T) applicationContext.getBean(name);
}
}
edit
The trouble from the latest example project;
#Service
public class ExampleService {
#Autowired
private Logger logger;
public ExampleService() {
this.logger=logger;
logger.info("Im working");
}
}
Here the Logger will be null, when the ExampleService constructor is triggered, since the constructor is called before the injection starts, but you can merge this behaviour if you incorporate the injection through the said constructor as follows;
#Service
public class ExampleService {
private final Logger logger;
public ExampleService(Logger logger) {
this.logger = logger;
logger.info("Im working");
}
}
Works perfectly without any trouble...

You should never be accessing beans programmatically like you did with this SpringContextUtil, just inject MarketDataRobot in the constructor of MdspiImpl and you’re good to go (since it’s annotated with #Service). The preferred way is to use constructor injection instead of field injection, which will make it easier for you to write unit tests. You can also get rid of #Autowired if you have only one constructor.

NoSuchBeanDefinitionException: No qualifying bean of type [duplicate]

This question already has an answer here:
What is a NoSuchBeanDefinitionException and how do I fix it?
(1 answer)
Closed 6 years ago.
I stack with above mentioned exception and really don't understate why it is appeared. I am using spring boot and declare bean through the annotation.
Application is executed by this class:
#SpringBootApplication
public class Application extends SpringBootServletInitializer {
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(Application.class);
}
public static void main(String[] args) throws Exception {
SpringApplication.run(Application.class, args);
}
My problem bean has the following declaration:
#Service
public class OrderSvc extends AbstractService implements DAOService {
I try to put it in the following bean:
#RestController
public class OrderController {
#Autowired
CarSvc carSvc;
#Autowired
OrderSvc orderSvc;
and the exception is appeared: Could not autowire field: biz.Services.OrderSvc biz.controllers.rest.administrator.OrderController.orderSvc; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [biz.Services.OrderSvc] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}
I have also CarSvc bean that is located at the same package as OrderSvc and extends the same classes but there are no problems with it injection
#Service
public class CarSvc extends AbstractService implements DAOService<Car> {
Do you have any ideas why this exception appears ?

Spring creates proxies for classes that declare #Transactional, so that it is able to add the transactional behaviour and intercepted calls to your object. If the bean extends any interface Spring is going to create a Dynamic Proxy using the JDK Reflection API and this can only be done by interface. The proxy is a new object implementing the same interface. So your target bean is not your implementation but a proxy. That is why you were getting a non qualify bean exception.
CGLIB, on the other hand, can create a proxy by subclassing.
So, to get it working, you need to change your bean type to the interface or you can configure cglib using #EnableTransactionManagement(proxyTargetClass = true).

Try to to autowire your beans using interfaces rather than implementations :
#RestController
public class OrderController {
#Autowired
#Qualifier("carSvc")
DAOService carSvc;
#Autowired
#Qualifier("orderSvc")
DAOService orderSvc;
}
Edit : But before that you have to give names to your services :
#Service("carSvc")
public class CarSvc extends AbstractService implements DAOService<Car> {}
#Service("orderSvc")
public class OrderSvc extends AbstractService implements DAOService<Order> {}
What's going on here is that Spring generate proxies of your services based on the CarSvc, OrderSvc and implement the DAOService but does not extend the CarSvc, OrderSvc.
//somthing like this
class CarSvcProxy implement DAOService {
public Object getOrder(Long id) {
try {
// ...
txManager.commit();
} catch (Exception ex) {
txManager.rollback();
}
}
}
#RestController
public class OrderController {
//So when you do this :
#Autowired
CarSvc carSvc;
//it's somehow like if you did :
CarSvc carSvc = new CarSvcProxy(); //carSvc != CarSvcProxy
//But this will work :
DAOService carSvc = new CarSvcProxy(); //because CarSvcProxy implement DAOService
}

I found the code which leads to exception but I really don't undestand why.
In my OrderSvc there is the following method:
#Transactional(readOnly = true)
public Object getOrder(Long id) {
final Order order = getDAO().findOne(id);
OrderDTO orderDTO = modelMapper.map(order, OrderDTO.class);
return orderDTO;
}
So if the annotation #Transactional(readOnly = true) was excluded the application can be excecuted without problem... Do you have any ideas why this annotation lead to NoSuchBeanDefinitionException ?

How to get bean using application context in spring boot

I am developing a SpringBoot project and I want to get the bean by its name using applicationContext. I have tried many solution from web but could not succeed. My Requirement is that I have a controller
ControllerA
and inside the controller I have a method getBean(String className). I want to get instance of registered bean. I have hibernate entities and I want to get an instance of the bean by passing the name of class only in getBean method.
Please help if someone know the solution.

You can Autowire the ApplicationContext, either as a field
#Autowired
private ApplicationContext context;
or a method
#Autowired
public void context(ApplicationContext context) { this.context = context; }
Finally use
context.getBean(SomeClass.class)

You can use ApplicationContextAware.
ApplicationContextAware:
Interface to be implemented by any object that wishes to be notified
of the ApplicationContext that it runs in. Implementing this interface
makes sense for example when an object requires access to a set of
collaborating beans.
There are a few methods for obtaining a reference to the application context. You can implement ApplicationContextAware as in the following example:
package hello;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
#Component
public class ApplicationContextProvider implements ApplicationContextAware {
private ApplicationContext applicationContext;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
public ApplicationContext getContext() {
return applicationContext;
}
}
Update:
When Spring instantiates beans, it looks for ApplicationContextAware implementations, If they are found, the setApplicationContext() methods will be invoked.
In this way, Spring is setting current applicationcontext.
Code snippet from Spring's source code:
private void invokeAwareInterfaces(Object bean) {
.....
.....
if (bean instanceof ApplicationContextAware) {
((ApplicationContextAware)bean).setApplicationContext(this.applicationContext);
}
}
Once you get the reference to Application context, you get fetch the bean whichever you want by using getBean().

actually you want to get the object from the Spring engine, where the engine already maintaining the object of your required class at that starting of the spring application(Initialization of the Spring engine).Now the thing is you just have to get that object to a reference.
in a service class
#Autowired
private ApplicationContext context;
SomeClass sc = (SomeClass)context.getBean(SomeClass.class);
now in the reference of the sc you are having the object.
Hope explained well. If any doubt please let me know.

Even after adding #Autowire if your class is not a RestController or Configuration Class, the applicationContext object was coming as null. Tried Creating new class with below and it is working fine:
#Component
public class SpringContext implements ApplicationContextAware{
private static ApplicationContext applicationContext;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws
BeansException {
this.applicationContext=applicationContext;
}
}
you can then implement a getter method in the same class as per your need to get the bean. Like:
applicationContext.getBean(String serviceName,Interface.Class)

Using SpringApplication.run(Class<?> primarySource, String... arg) worked for me. E.g.:
#SpringBootApplication
public class YourApplication {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(YourApplication.class, args);
}
}

As an alternative approach you can use ConfigurableApplicationContext to get bean of any class which is annotated with #Component, #Repository or #Service.
Let's say you want to get a bean of the class BaseComponent :
#Service
public class BaseComponent {
public String getMessage() {
return "hello world";
}
}
Now you can use ConfigurableApplicationContext to get the bean:
#Component
public class DemoComponent {
#Autowired
ConfigurableApplicationContext applicationContext;
public BaseComponent getBeanOfBaseComponent() {
return applicationContext.getBean(BaseComponent.class);
}
}

You can use the ApplicationContextAware class that can provide the application context.
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext ctx = null;
public static ApplicationContext getApplicationContext() {
return ctx;
}
#Override
public void setApplicationContext(final ApplicationContext ctx) throws BeansException {
ApplicationContextProvider.ctx = ctx;
}
/**
* Tries to autowire the specified instance of the class if one of the specified
* beans which need to be autowired are null.
*
* #param classToAutowire the instance of the class which holds #Autowire
* annotations
* #param beansToAutowireInClass the beans which have the #Autowire annotation
* in the specified {#classToAutowire}
*/
public static void autowire(Object classToAutowire, Object... beansToAutowireInClass) {
for (Object bean : beansToAutowireInClass) {
if (bean == null) {
ctx.getAutowireCapableBeanFactory().autowireBean(classToAutowire);
}
}
}
}

If you are inside of Spring bean (in this case #Controller bean) you shouldn't use Spring context instance at all. Just autowire className bean directly.
BTW, avoid using field injection as it's considered as bad practice.

One API method I use when I'm not sure what the bean name is org.springframework.beans.factory.ListableBeanFactory#getBeanNamesForType(java.lang.Class<?>). I simple pass it the class type and it retrieves a list of beans for me. You can be as specific or general as you'd like to retrieve all the beans associated with that type and its subtypes, example
#Autowired
ApplicationContext ctx
...
SomeController controller = ctx.getBeanNamesForType(SomeController)

Easy way in configration class call the BEAN annoted method . Yes u heard it right---- :P calling SpringBoot #Bean annoted method return the same bean from config .I was trying to call a logout in #predestroy method in config class from a bean and direcltly called the method to get the same bean .
P.S. : I added debug in the #bean annotated method but it didn't entered the method even when i called it.Sure to blame -----> Spring Magic <----

You can use ServiceLocatorFactoryBean. First you need to create an interface for your class
public interface YourClassFactory {
YourClass getClassByName(String name);
}
Then you have to create a config file for ServiceLocatorBean
#Configuration
#Component
public class ServiceLocatorFactoryBeanConfig {
#Bean
public ServiceLocatorFactoryBean serviceLocatorBean(){
ServiceLocatorFactoryBean bean = new ServiceLocatorFactoryBean();
bean.setServiceLocatorInterface(YourClassFactory.class);
return bean;
}
}
Now you can find your class by name like that
#Autowired
private YourClassfactory factory;
YourClass getYourClass(String name){
return factory.getClassByName(name);
}

Just use:
org.springframework.beans.factory.BeanFactory#getBean(java.lang.Class)
Example:
#Component
public class Example {
#Autowired
private ApplicationContext context;
public MyService getMyServiceBean() {
return context.getBean(MyService.class);
}
// your code uses getMyServiceBean()
}