using html:radio, struts should automatically checks the radio button if the value of the form-bean is set. you can set the 'initial' attribute of the form-property in the form-bean definition of the struts-config.xml...e.g intitial="j".

if you are not using DynaActionForm, simply default the value when declaring the variable, e.g String r = "j"; .

you can also initialize form-bean value using form.set("r","j"); where 'form' is the local reference to the mapped form-bean to the action class.