Spring. Spring Container

 Primary functions:

1. Create and manage objects (Inversion of Control)

2. Inject object's dependencies (Dependency Injection)

Configuring Spring Container

1. XML configuration file 

2. Java Annotations (modern)

3. Java Source Code (modern)

Spring container is generally known as ApplicationContext.

A "Spring Bean" is simply a Java object. When Java objects are created by the Spring Container, 

then Spring refers to them as "Spring Beans".

<?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:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd">

   <bean id = "myCoach" class="com.example.demo.TrackCoach">
   </bean>

</beans>

package com.example.demo;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class HelloSpringApp {
    public static void main(String[] args) {

        // load the spring configuration file
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        // retrieve bean from spring container
        Coach theCoach = context.getBean("myCoach", Coach.class);

        // call methods on the bean
        System.out.println(theCoach.getDailyWorkout());

        // close the context
        context.close();
    }
}