A value type is a type which doesn't have existence of its own, but belongs to an entity, like an user and his address. Value types are always completely owned by their containing entity.

We will embed an Address class inside a User class. The simplest way to embed a value type in an entity class is to treat the member variables of the embedded class (e.g. Address), the same way as we treat the member variables of the embedding class (e.g. User) by adding more columns to the entity table one column each for the value type class members

When you load an embeding class, it may load its embedded collections either lazily or eagerly.

Important points about eager and lazy fetch types in Hibernate

1. By default, when you load an embedding class (E.g. User or Company) using session.get,

   • its embedded collections (E.g. AddressList or EmployeeList) is not actually retrieved from database, but only the top level fields are retrieved.

We will further analyze the lab excercise done @ http://javajee.com/lab-creating-a-soap-web-service-bottoms-up-using-endp....

Service Endpoint Interface (SEI)

We had used the below SEI for creating the web service:

package com.javajee.ws.tsexample1;

@WebService
public interface TimeService
{
         @WebMethod
         String getTimeFromServer();
}

Knowledge of HTTP, Servlets and Servers

We will be focussing on learning about web services with HTTP as the transport protocol and will be deploying web services on web containers as well as application servers . So a decent knowledge about these are good to have.

You can learn more about these @ http://javajee.com/java-ee-web-components-part1-http-and-servlets.

While creating a web service bottom up, we can configure the SEI and SIB to act as a web service using annotations. In case of bottom up web service, the binding properties in a WSDL can be specified using these annotations.

Summary of common annotations used to create web services

@WebService annotation 

• May be used on:

  • SEI to denote that it is a Web Service interface