InvalidCancelException in Struts 1.1

Hello,

I'm using Struts 1.1 and Tomcat 6.

I've a form in my app with 2 buttons Submit and Cancel.

When I click on Submit , it works fine and I get Success.jsp (mentioned in mapping.forward).

However, When I click on Cancel, I get http 500 error with following details :-

exception

javax.servlet.ServletException: org.apache.struts.action.InvalidCancelException
	org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:520)
	org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:202)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

root cause

org.apache.struts.action.InvalidCancelException
	org.apache.struts.action.RequestProcessor.processValidate(RequestProcessor.java:941)
	org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:198)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

This is my Action class :-

package app1;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class CustomerAction extends Action{

@Override
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {

if(isCancelled(request)){
			System.out.println("Cancel operation performed.");
			return mapping.findForward("mainpage");
			
		}
		
		CustomerForm custForm = (CustomerForm) (form);
		
		ActionForward forward = null;
		
		if ("step".equals(custForm.getStep())) {
			
			System.out.println("Save button clicked.");
		
		String firstName = custForm.getFirstName();
		String lastName = custForm.getLastName();
		
		System.out.println("the first name is " + firstName);
		System.out.println("the last name is " + lastName);
		
		 forward = mapping.findForward("success");
		}
		return forward;
	}
}

Below is my Struts-config.xml file :-

This is my message resource bundle file which works fine.

prompt.customer.firstname= First Name
prompt.customer.lastname = Last Name

button.save = Save
button.cancel = Cancel

error.cust.firstname.null= First name is required

This is CustomerDetails.jsp file having these buttons : -

I googled it, it was mentioned that the mentioned error pops up when the Cancel mapping is missing something.
But everything looks fine in my case i.e. mainpage and corresponding index.jsp

One thing I need to know is that how to map the Cancel button's submit event with the isCancelled method which is provided in Struts.
I think Struts automatically maps it with the method using introspection.

Am I right ?
Please advise.

Pramod,
I'm having the same problem (although it surfaced when I upgraded from struts 1.1 to struts 1.3). Your code looks good to me - have you found a solution?

My problem got solved with cancellable="true" as shown below: