Clear up concept of validation() call

[Anjib Mulepati]

Hi everyone

I got confuse with the call of ActionForm in Struts 1.3.8
If I have Form as follow with validate() method

public class MyTestForm extends org.apache.struts.action.ActionForm {

     String myTestString;

    public MyTestForm() {
        super();
    }

    public String getMyTestString() {
        return myTestString;
    }

    public void setMyTestString(String newString) {
        this.myTestString =newString;
    }

    @Override
    public ActionErrors validate(ActionMapping mapping, 
HttpServletRequest request) {
        ActionErrors errors = new ActionErrors();
        //do validation of myTestString
        return errors;
   }

}

And I have Action class as

public class UploadAction extends org.apache.struts.action.Action {

    public ActionForward execute(ActionMapping mapping, ActionForm form,
            HttpServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {
                        MyTestForm myForm = (MyTestForm) form;
                        //Other operation
   }
}

Now when I debug with debugging point at both validate() and execute() 
method's first statement what i found is the control never goes to 
validate() method. I was guessing control should go to validate method 
first then only to execute method. In other word my input was never 
validated.

What I am doing wrong? Can anyone help me out in this?

Thanks in advance
Anjib