Hibernate notes by Sekhar sir from Naresh i Technologies

Hibernate notes (material) by Mr.Sekhar sir is given in PDF file format to download. I have given many pdf materials of Sekhar sir like Spring , WebServices, and XML notes. He covered all the topics in Spring with different modules. Currently Sekhar sir is working with Sathya Technologies. In this Hibernate class notes he covered all the Hibernate interview Questions and differences between load and get methods and about lazy loading. I am sure that you can easily understand the hibernate class notes.

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Struts DispatchAction Example Application

Struts DispatchAction can group similar action classes into a single action class having different methods.
In this action excluding the execute method we can write our own user defined methods.The parameters are same given by struts framework (mapping,form,request,response).

In this example we will see how to group similar action methods in a single Class like add,sub,mul,div.In a single page we are performing four actions with different buttons.

In our example our Actionclass (CalculateAction) should extends DispatchAction to dispatch the action based on the parameter value of action button.Here we should concentrate how the action is performing.

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What is lazy loading in Hibernate?

Lazy setting decides whether to load child objects while loading the Parent Object.You need to do this setting respective hibernate mapping file of the parent class.lazy = true (means not to load child)By default the lazy loading of the child objects is true. This make sure that the child objects are not loaded unless they are explicitly invoked in the application by calling getChild() method on parent.In this case hibernate issues a fresh database call to load the child when getChild() is actully called on the Parent object.But in some cases you do need to load the child objects when parent is loaded. Just make the lazy=false and hibernate will load the child when parent is loaded from the database.

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Difference between load( ) vs get( ) in Hibernate

The following Hibernate code snippet retrieves a User object from the database:

load()
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1). Only use the load()method if you are sure that the object exists.
2). load() method will throw an exception if the unique id is not found in the database.
3). load() just returns a proxy by default and database won’t be hit until the proxy is first invoked.

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How ActionServlet acting as a FrontController.in Struts

A special web resource of web application that traps request comming to other web application to execute common and global pre request processing logic by username and password is called "Front Controller".

Servlet acting as a Front-controller , then it is called Front-controller servlet. If JSP is acting as Front-controller then it is called Front-controller JSP.

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4) . Inner Communication in Struts

The communication between files or modules.

1. ActionServlet
2. JSP's
3. Web.xml
4. ActionBeans / FormBean
5. ActionClass
6. ActionForward
7. Struts Configuration file

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