What is the purpose of tiles-def.xml file, resourcebundle.properties file, validation.xml file?

1. tiles-def.xml

tiles-def.xml is used as a configuration file for an appliction during tiles development
You can define the layout / header / footer / body content for your View.

Eg:

<tiles-definitions>
<definition name="siteLayoutDef" path="/layout/thbiSiteLayout.jsp">
<put name="title" value="Title of the page" />
<put name="header" value="/include/thbiheader.jsp" />
<put name="footer" value="/include/thbifooter.jsp" />
<put name="content" type="string">
Content goes here
</put>
</definition>
</tiles-definitions>

<tiles-definitions>
<definition name="userlogin" extends="siteLayoutDef">
<put name="content" value="/dir/login.jsp" />
</definition>
</tiles-definitions>

2. validation.xml

The validation.xml file is used to declare sets of validations that should be applied to Form Beans.

Each Form Bean you want to validate has its own definition in this file
Inside that definition, you specify the validations you want to apply to the Form Bean's fields.

Eg:

<form-validation>
<formset>
<form name="logonForm">
<field property="username"
depends="required">
<arg0 key=" prompt.username"/>
</field>
<field property="password"
depends="required">
<arg0 key="prompt.password"/>
</field>
</form>
</formset>
</form-validation>

3. Resourcebundle.properties

Instead of having hard-coded error messages in the framework, Struts Validator allows you to specify a key to a message in the ApplicationResources.properties (or resourcebundle.properties) file that should be returned if a validation fails.

Eg:

In ApplicationResources.properties

errors.registrationForm.name={0} Is an invalid name.

In the registrationForm.jsp

<html:messages id="messages" property="name">
<font color="red">
<bean:write name="messages" />
</html:messages>

Output(in red color) : abc Is an invalid name