Now that you know how to set primitives, let's do the coding for reference configuration as well. We will use the same DI_using_namespace project to develop the code further:

1. Copy or create an Address class (refer to the code from Ch02_Reference_DI) in the com.ch02.beans package.
2. Copy or create a Customer class (refer to the code from Ch02_Reference_DI) in the com.ch02.beans package.
3. Add a bean for Address using setter DI in beans.xml.

4. Add a bean for Customer using namespace p, and the configuration will look like the following code:

<bean id="customer" class="com.ch02.beans.Customer" 
  p:cust_id="2013" p:cust_name="It's Bob" 
  p:cust_address-ref="cust_address"> 
</bean> 

You can observe here that the customer address is not primitive, so, instead of using value, we use the reference as p:cust_address-ref ="cust_address', where cust_address is the id representing the Address bean.

5. Create TestCustomer with the main function containing the following code:

public static void main(String[] args) { 
  // TODO Auto-generated method stub 
  ApplicationContext context=new 
  ClassPathXmlApplicationContext("beans.xml"); 
  Customer customer=(Customer)context.getBean("customer"); 
  System.out.println(customer.getCust_name()+"	"+ 
  customer.getCust_id()); 
} 

6. The execution of code will show the following output: