The j:set tag is used to set a variable and its value. It accepts the following attributes:

• var: The name of the variable
• value: The value of the variable. This is a Jelly expression and can be used to include variables that contain ${jvar_curly_brackets} and $[jvar_square_brackets]
• defaultValue: If the value evaluates to null or is empty, then the value specified in the defaultValue attribute is set to the variable

For example:

<j:setvar="jvar_booking_request_number"  
value="${jvar_gr.getValue('number')}"/>