Let's take an example of a Car to make it crystal clear how the container creates its object using the following steps:

1. Create a Java application Ch02_Instance_Creation, and add jars that we added in the previous project.
2. Create a Car class in the com.ch02.beans package with chassis_number, color, fuel type, price, and average as data members. The code is as follows:

class Car{ 
  private String chassis_number, color, fuel_type; 
  private long price; 
  private double average; 
}
 

3. Add show() in Car as shown in the following lines of code:

public void show() 
{ 
  System.out.println("showing car "+chassis_number +" having 
  color:-"+color+"and price:-"+price); 
} 

4. When the developer tries to create the object, the code will be as follows:

Car car_obj=new Car(); 

Now we need to configure BeanDefination in the XML file that represents a bean instance so that it will be managed by the Spring container.

Create instance.xml in Classpath to configure our Car BeanDefination; we will need to configure it as follows:

<bean id="car_obj" class="com.ch02.beans.Car"/> 
</beans> 

5. Create Test_Car with the main function in a default package to get the bean to use business logic as follows:
   • Get a Spring container instance. We will use ClassPathXmlApplicationContext, as discussed in the container initialization.
   • Get the bean instance from the container.
   • Perform business logic using the bean instance.

The code will be as follows:

public class Test_Car { 
  Public static void main(String[] args) { 
    // TODO Auto-generated method stub 
    ApplicationContext context=new 
      ClassPathXmlApplicationContext("instance.xml"); 
    Car car=(Car)context.getBean("car_obj"); 
      car.show(); 
  } 
} 

6. The output is as shown in the following screenshot:

It's pretty clear from the output that the container has used the default constructor to define the values. Let's prove it by adding a default constructor in Car by following this code:

public Car() { 
  // TODO Auto-generated constructor stub 
  chassis_number="eng00"; 
  color="white"; 
  fuel_type="diesel"; 
  price=570000l; 
  average=12d; 
} 

The updated output is as shown in the following screenshot: