org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoRestController'

Question

I am new to Spring and I am try to make a application for learning but I am getting problem in Autowiring,I am adding my code. I am working on spring boot.

Spring Boot Code

public class DemoApplication {      public static void main(String[] args) {         SpringApplication.run(DemoApplication.class, args);     } } 

LoginBean.java

@Service @Component public class LoginBean {     private String userId;     private String pwd;      public String getUserId() {         return userId;     }      public void setUserId(String userId) {         this.userId = userId;     }      public String getPwd() {         return pwd;     }      public void setPwd(String pwd) {         this.pwd = pwd;     } 

DemoRestController.java

@RestController @EnableAutoConfiguration @RequestMapping("/demo") @Component public class DemoRestController {       private final LoginBean loginBean;      @Autowired     public DemoRestController(LoginBean loginBean) {         this.loginBean=loginBean;     }      @RequestMapping(value = "/login/{id},{pwd}", method = RequestMethod.GET, produces = "application/json")     public @ResponseBody LoginBean loginService(@PathVariable String id, @PathVariable String pwd) {         //LoginBean loginBean = new LoginBean();          loginBean.setUserId(id);         loginBean.setPwd(pwd);         return loginBean;     } 

I tried following scenarios to make my @Autowired work:

1. @Autowired to LoginBean loginBean;
2. Created getter setter of LoginBean in Controller class and autowired setters;
3. Created constructor of Controller and autowired, as given in above code;

Below is the error which I am getting

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoRestController': Unsatisfied dependency expressed through constructor argument with index 0 of type [com.ag.digital.demo.bean.LoginBean]: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}     at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:185) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]     at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]     at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]     at com.ag.digital.demo.boot.DemoApplication.main(DemoApplication.java:14) [classes/:na] Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.ag.digital.demo.bean.LoginBean] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}     at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1373) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1119) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]     ... 19 common frames omitted 

Answer 1

Your DemoApplication class is in the com.ag.digital.demo.boot package and your LoginBean class is in the com.ag.digital.demo.bean package. By default components (classes annotated with @Component) are found if they are in the same package or a sub-package of your main application class DemoApplication. This means that LoginBean isn't being found so dependency injection fails.

There are a couple of ways to solve your problem:

1. Move LoginBean into com.ag.digital.demo.boot or a sub-package.
2. Configure the packages that are scanned for components using the scanBasePackages attribute of @SpringBootApplication that should be on DemoApplication.

A few of other things that aren't causing a problem, but are not quite right with the code you've posted:

• @Service is a specialisation of @Component so you don't need both on LoginBean
• Similarly, @RestController is a specialisation of @Component so you don't need both on DemoRestController
• DemoRestController is an unusual place for @EnableAutoConfiguration. That annotation is typically found on your main application class (DemoApplication) either directly or via @SpringBootApplication which is a combination of @ComponentScan, @Configuration, and @EnableAutoConfiguration.