Autowired annotation error in spring with java

Question

I have created a package com.springcore.autowire.Annotations which contains 4 files Emp.java, Address.java, awannconfig.xml, Test.java.

Emp.java contains class Emp with code as -

package com.springcore.autowire.Annotations;

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

public class Emp {

    private Address address;

    public Address getAddress() {
        return this.address;
    }

    @Autowired
    @Qualifier("address")
    public void setAddress(Address address) {
        this.address = address;
    }

    public Emp(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "{" + " address='" + getAddress() + "'" + "}";
    }

}

Address.java contains class Address with code-

package com.springcore.autowire.Annotations;

public class Address {
    private String street;
    private String city;

    public String getStreet() {
        return this.street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getCity() {
        return this.city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public Address(String street, String city) {
        this.street = street;
        this.city = city;
    }

    @Override
    public String toString() {
        return "{" + " street='" + getStreet() + "'" + ", city='" + getCity() + "'" + "}";
    }

}

awannconfig.xml file -

<?xml version="1.0" encoding="UTF-8"?>
<!-- We get this template from documentation -->
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:annotation-config />
    <bean class="com.springcore.autowire.Annotations.Emp" name="emp" />

    <bean class="com.springcore.autowire.Annotations.Address" name="address">
        <property name="street" value="PA-24" />
        <property name="city" value="Muradnagar" />
    </bean>
    <!-- more bean definitions go here -->
</beans>

Test.java contains Test class with main method to check use of @Autowired annotations.

package com.springcore.autowire.Annotations;

import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.context.ApplicationContext;

public class Test {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("com/springcore/autowire/Annotations/awannconfig.xml");

        Emp obj = (Emp) context.getBean("emp");
        System.out.println(obj);

    }
}

When I run Test.java file it is showing this exception -

Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'emp' defined in class path resource [com/springcore/autowire/Annotations/awannconfig.xml]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'address' defined in class path resource [com/springcore/autowire/Annotations/awannconfig.xml]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'java.lang.String' available: expected at least 1 bean which qualifies as autowire candidate. Dependency 
annotations: {}

Please help with this code as I cannot see any error.

Answer 1

The issue is coming due to parameterised constructor in the Address class whose constructor expects two parameters to be used to create a bean or object when you autowire it as there is no default constructor available.

Solution of the issue.

Keep Emp class as it is:

public class Emp {

    private Address address;

    public Address getAddress() {
        return this.address;
    }

    @Autowired
    @Qualifier("address")
    public void setAddress(Address address) {
        this.address = address;
    }

    public Emp(Address address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "{" + " address='" + getAddress() + "'" + "}";
    }

}

Keep Address class it is:

public class Address {
    private String street;
    private String city;

    public String getStreet() {
        return this.street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getCity() {
        return this.city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public Address(String street, String city) {
        this.street = street;
        this.city = city;
    }

    @Override
    public String toString() {
        return "{" + " street='" + getStreet() + "'" + ", city='" + getCity() + "'" + "}";
    }

}

Update awannconfig.xml to this:

<?xml version="1.0" encoding="UTF-8"?>
<!-- We get this template from documentation -->
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:annotation-config />
    <bean class="com.springcore.autowire.Annotations.Emp" name="emp" />

    <bean class="com.springcore.autowire.Annotations.Address" name="address">
         <constructor-arg value="PA-24" type="String"/>
         <constructor-arg value="Muradnagar" type="String"/>
    </bean>
    <!-- more bean definitions go here -->
</beans>

Output on my console.

{ address='{ street='PA-24', city='Muradnagar'}'}

Remember: Don't mix both constructor or setter injection as this will lead to confusion and unwanted errors.

Answer 2

Change bean configuration with constructor arg dependency injection, you missed that in emp bean definition. Change bean definition like below.

<bean class="com.springcore.autowire.Annotations.Emp" id="emp">
 <constructor-arg ref = "address"/>
</bean>

<bean class="com.springcore.autowire.Annotations.Address" id="address">
        <property name="street" value="PA-24" />
        <property name="city" value="Muradnagar" />
</bean>