Error in running sample Spring annotation based program without any xml - spring

Question

Hi I am trying to run a simple spring annotation based program without using any xml based configuration. I'm getting the error "Unsatisfied dependency expressed through field".
I learnt that using #ComponentScan spring scans the package mentioned and look for beans annotated.
Putting the code herein. My project is a maven project with hierarchy like MyProject/src/java/SpringAnnotnDemo/autowireAnnotationBased
There are three classed
Department.java
Employee.java
MainClass.java --> The main class
Department.java
package SpringAnnotnDemo.autowireAnnotationBased;
import org.springframework.stereotype.Component;
#Component
public class Department {
private String department;
public String getDeptName() {
return department;
}
public void setDeptName(String deptName) {
this.department = deptName;
}
}
Employee.java
package SpringAnnotnDemo.autowireAnnotationBased;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
#Component
public class Employee {
private int eid;
private String ename;
#Autowired
private Department department;
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public void showEployeeDetails() {
System.out.println("Employee Id : " + eid);
System.out.println("Employee Name : " + ename);
department.setDeptName("Mechanical Engineering");
System.out.println("Department : " + department.getDeptName());
}
}
MainClass.java
package SpringAnnotnDemo.autowireAnnotationBased;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
#Configuration
#ComponentScan("SpringAnnotnDemo.autowireAnnotationBased")
public class MainClass {
public static void main(String[] args) {
ApplicationContext ctx = new AnnotationConfigApplicationContext(Employee.class);
Employee emp = ctx.getBean(Employee.class);
emp.setEid(374);
emp.setEname("S.C.B");
emp.showEployeeDetails();
}
}
On running this simple program I am getting an error as below.
`Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'employee': Unsatisfied dependency expressed through field 'department'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'SpringAnnotnDemo.autowireAnnotationBased.Department' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}`
Can anyone please help me figure out what am I missing. I want the most simplest form of using annotation based spring without using any xml based configuration.

Answer 1

Change your this line
ApplicationContext ctx = new AnnotationConfigApplicationContext(Employee.class);
to this line
ApplicationContext ctx = new AnnotationConfigApplicationContext(MainClass.class);