@Autowired - No qualifying bean of type found for dependency at least 1 bean

Question

Currently I'm facing an issue in Autowire configuration between controller and the service layer.

I'm unable to trace my mistakes.

Simple Log Info

    SEVERE:   Exception while loading the app
    SEVERE:   Undeployment failed for context /OTT
    SEVERE:   Exception while loading the app : java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: org.apache.catalina.LifecycleException: org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type [com.ott.service.EmployeeService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

Below I have also given the Controller and Service Layer code and also the dispatcher-servlet.xml

Controller

package com.ott.controller;

import com.ott.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

    /**
     *
     * @author SPAR
     */
    @Controller
    public class AdminController {

        private EmployeeService employeeService;

        @RequestMapping("/employee")
        public String employee(){
            this.employeeService.fetchAll();
            return "employee";
        }

        @Autowired(required = true)
        @Qualifier(value="employeeService")
        public void setEmployeeService(EmployeeService empService) {
            this.employeeService = empService;
        }

    }

Service Interface

package com.ott.service;

import com.ott.hibernate.Employee;
import java.util.List;

/**
 *
 * @author SPAR
 */
public interface EmployeeService {

     List<Employee> fetchAll();


}

Service Interface Impl

package com.ott.service;

import com.ott.dao.EmployeeDAO;
import com.ott.hibernate.Employee;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

/**
 *
 * @author SPAR
 */
@Service
public class EmployeeServiceImpl implements EmployeeService{

    private EmployeeDAO employeeDAO;

    @Override
    @Transactional(readOnly = true)
    public List<Employee> fetchAll() {

        List<Employee> employees = employeeDAO.fetchAll();
        for (Employee employee : employees) {

            System.out.println("Name : "+employee.getFirst_Name() +" "+ employee.getLast_Name());

            System.out.println("Email Id : "+employee.getEmail_Id());
        }

        return employees;
    }

    @Autowired(required = true)
    @Qualifier(value="employeeDAO")
    public void setEmployeeDAO(EmployeeDAO empDAO) {
        this.employeeDAO = empDAO;
    }
}

Dispatcher-servlet.xml

 <?xml version='1.0' encoding='UTF-8' ?>
    <!-- was: <?xml version="1.0" encoding="UTF-8"?> -->
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:p="http://www.springframework.org/schema/p"
           xmlns:aop="http://www.springframework.org/schema/aop"
           xmlns:tx="http://www.springframework.org/schema/tx"
           xmlns:context="http://www.springframework.org/schema/context"
           xmlns:mvc="http://www.springframework.org/schema/mvc"       
           xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
           http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

        <context:component-scan base-package="com.ott.controller"/>
        <context:component-scan base-package="com.ott.hibernate"/>
        <context:component-scan base-package="com.ott.service"/>
        <context:component-scan base-package="com.ott.dao"/>

        <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/>
        <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>

        <mvc:resources mapping="/resources/**" location="/resources/" />

         <bean id="tilesConfigurer" class="org.springframework.web.servlet.view.tiles3.TilesConfigurer">
            <property name="definitions">
                <list>
                    <value>/WEB-INF/tiles-def/general-layout.xml</value>
                </list>
            </property>
        </bean>

        <bean id="viewResolverTiles" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
            <property name="viewClass" value="org.springframework.web.servlet.view.tiles3.TilesView"/>
        </bean> 

        <mvc:annotation-driven />

        <bean
          class="org.springframework.web.servlet.view.InternalResourceViewResolver">
          <property name="prefix">
            <value>/WEB-INF/pages/</value>
          </property>
          <property name="suffix">
            <value>.jsp</value>
          </property>
        </bean>
    </beans>

Answer 1

Guys I found the issue

I just tried by adding the qualifier name in employee service finally it solved my issue.

@Service("employeeService")

public class EmployeeServiceImpl implements EmployeeService{

}

Answer 2

You don't have to necessarily provide name and Qualifier. If you set a name, that's the name with which the bean is registered in the context. If you don't provide a name for your service it will be registered as uncapitalized non-qualified class name based on BeanNameGenerator. So in your case the Implementation will be registered as employeeServiceImpl. So if you try to autowire with that name, it should resolve directly.

private EmployeeService employeeServiceImpl;

@RequestMapping("/employee")
public String employee() {
    this.employeeService.fetchAll();
    return "employee";
}

@Autowired(required = true)
public void setEmployeeService(EmployeeService employeeServiceImpl) {
    this.employeeServiceImpl = employeeServiceImpl;
}

@Qualifier is used in case if there are more than one bean exists of same type and you want to autowire different implementation beans for various purposes.