JAVA EE: What is Constructor injection type ambiguities in Spring?

Sunday 15 July 2018

What is Constructor injection type ambiguities in Spring?

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What is Constructor injection type ambiguities in Spring?

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0%20http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ram.core</groupId>

    <artifactId>SpringDemo</artifactId>

    <packaging>jar</packaging>

    <version>1.0-SNAPSHOT</version>

    <name>SpringDemo</name>

    <url>http://maven.apache.org</url>

    <properties>

        <spring.version>5.0.2.RELEASE</spring.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>3.8.1</version>

            <scope>test</scope>

        </dependency>

        <!-- Spring 5 dependencies -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-core</artifactId>

            <version>${spring.version}</version>

        </dependency>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context</artifactId>

            <version>${spring.version}</version>

        </dependency>

    </dependencies>

</project>

Employee.java

package com.ram.core.model;

public class Employee

{

    private String name;

    private String address;

    private int age;

    public Employee(String name, String address, int age)

    {

        this.name = name;

        this.address = address;

        this.age = age;

    }

    public Employee(String name, int age, String address)

    {

        this.name = name;

        this.age = age;

        this.address = address;

    }

    @Override

    public String toString()

    {

        return "Employee [name=" + name + ", address=" + address + ", age="

                + age + "]";

    }

}

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-4.3.xsd">

    <bean id="employee" class="com.ram.core.model.Employee">

        <constructor-arg type="java.lang.String">

            <value>Peter</value>

        </constructor-arg>

        <constructor-arg type="int">

            <value>32</value>

        </constructor-arg>

        <constructor-arg type="java.lang.String">

            <value>1888</value>

        </constructor-arg>

    </bean>

</beans>

App.java

package com.ram.core;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ram.core.model.Employee;

public class App

{ 

    public static void main(String[] args)

    {

        ApplicationContext context = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

        System.out.println("---------------------------------------");

        Employee employee = (Employee) context.getBean("employee");

        System.out.println(

                "Got employee object from the ApplicationContext(Spring container)");

        System.out.println(employee);

    }

}

Output

Jun 26, 2018 9:13:32 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh

INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@5b37e0d2: startup date [Tue Jun 26 09:13:32 IST 2018]; root of context hierarchy

Jun 26, 2018 9:13:32 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

INFO: Loading XML bean definitions from class path resource [applicationContext.xml]

---------------------------------------

Got employee object from the ApplicationContext(Spring container)

Employee [name=Peter, address=1888, age=32]