package mypackage;

import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;

public class VariableResolverImpl extends
        org.apache.myfaces.el.VariableResolverImpl {
    private static final String ERROR_FLAG = "error";
    private static final String EXCEPTION_TYPE = "exception";
    
    @Override
    public Object resolveVariable(FacesContext facesContext, String name) {
        try {
            return super.resolveVariable(facesContext, name);
        } catch (Throwable e) {
            HttpServletRequest request = (HttpServletRequest)facesContext.getExternalContext().getRequest();
            
            request.setAttribute(ERROR_FLAG, Boolean.TRUE);
            request.setAttribute(EXCEPTION_TYPE, e);
            
            throw new RuntimeException(e);
        }
    }
    
}

<faces-config>
<!--  Application Config -->
<application>
  <variable-resolver>mypackage.VariableResolverImpl</variable-resolver>
  <!-- other configuration here -->
</application>

<!-- other configuration here -->

</faces-config>

public class AppFilter implements Filter {
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
            ServletException {

        try {
            chain.doFilter(request, response);
        } catch (ServletException e) {
            
            Boolean error =  (Boolean)request.getAttribute("error");
            if (Boolean.TRUE.equals(error)) {
                Throwable te = (Throwable)request.getAttribute("exception");
                
                if (te instanceof AppException) {
                    //TODO do business here
                    
                } else {
                    //TODO do business here
            }
            } else {
            //TODO do business here
        }

        }

}