The variable-resolver element contains the fully qualified class name of the concrete VariableResolver implementation class that is used during the processing of value reference expressions.
To add a variable resolver:
Select faces-config.xml in the Project Explorer of the J2EE perspective.
The JSF Application Configuration editor opens.
Select the Other tab of the editor.
The Other page appears.
Expand the Variable Resolver section.
Click Add.
The Find Type dialog box opens.
Type the first letter of the type you want to use in the Select a type field.
A list of available types beginning with the letter you typed appears in the Matching types list.
Select the type that you want to use and click OK.
The variable resolver is added to the list.