Hi, please help me to find out what i am doing wrong. following is my code;

.jsp file

Code:
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@include  file="../header.jsp" %>
<form:form method="POST" action="activity.htm?action=saveActivity" commandName="activity">
    <table>
        <td>Activity Name : </td>
        <td><form:input path="activityName" /></td>
        <td><form:errors path="activityName" cssClass="error" /></td>
        </tr>
                      <tr>
                    <td><input type="submit" value="Save"></td>
                    <td><input type="reset" value="Clear"></td>
                </tr>      
    </table>
</form:form>
<%@include  file="../footer.jsp" %>
ActivityValidator.java
Code:
import com.towertech.eec.model.Activity;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;

public class ActivityValidator implements Validator{
    
    	@Override
	public boolean supports(Class clazz) {
		return Activity.class.isAssignableFrom(clazz);
	}

	@Override
	public void validate(Object target, Errors errors) {
		Activity obj = (Activity)target;
		if(obj.getActivityName()!= null && obj.getActivityName().length()>100){
			errors.rejectValue("activityName", "lengthExceed.activityName");
		}
	}
}
part of ActivityController.java
Code:
//==called when add button pressed in in view page
 public ModelAndView addActivity(HttpServletRequest request, HttpServletResponse response,Activity activity) throws Exception {
        if(map.get("CAN_ADD").toString().equals("Y")){
            ModelAndView mv = new ModelAndView("setup/addActivity", "refData", map);
            mv.addObject("activity",activity);
            return mv;
        } else{
            map.put("msg",Utility.setDisplayMessage("You do not have right to add new Activity.", "fail"));
            return new ModelAndView("setup/viewActivity", "refData", map);
        }
    }

//==called when save button pressed in .jsp
    public ModelAndView saveActivity(HttpServletRequest request, HttpServletResponse response, Activity activity) throws Exception {
        boolean flag=false;
        String msg;
        if(map.get("CAN_ADD").toString().equals("Y")){
            flag = this.serviceFactory.getActivityService().saveActivity(activity, userName);     
            if(flag){
                msg=Utility.setDisplayMessage("New activity added successfully", "success");
            }else{
                msg=Utility.setDisplayMessage("Error occured while adding new activity", "fail");
            }
            map.put("msg",msg);
            
        } else{
            map.put("msg",Utility.setDisplayMessage("You do not have right to add new Activity.", "fail"));
            return new ModelAndView("setup/viewActivity", "refData", map);
        }

        ModelAndView mv = new ModelAndView("setup/addActivity", "refData", map);
        mv.addObject("activity",activity);
        return mv;
    }
applicationContext.xml
Code:
    <bean id="activityController" class="com.towertech.eec.controller.ActivityController">
        <property name="methodNameResolver" ref="actions"/>
        <property name="serviceFactory" ref="serviceFactory"/>
        		<!-- Map a validator -->
        <property name="validators">
            <bean class="com.towertech.eec.validator.ActivityValidator" />
	</property>
    </bean>

<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <property name="basename" value="/WEB-INF/messages" />
    </bean>
messages.properties
Code:
required.activityName = Username is required!
lengthExceed.activityName = exceeded
following error occur when i try to save by adding Activity Name field greater than 100 characters;

Code:
HTTP Status 500 - Errors binding onto object 'command'; nested exception is org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors

type Exception report

message Errors binding onto object 'command'; nested exception is org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.bind.ServletRequestBindingException: Errors binding onto object 'command'; nested exception is org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'command' on field 'activityName': rejected value [12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901]; codes [lengthExceed.activityName.command.activityName,lengthExceed.activityName.activityName,lengthExceed.activityName.java.lang.String,lengthExceed.activityName]; arguments []; default message [null]
	org.springframework.web.bind.ServletRequestDataBinder.closeNoCatch(ServletRequestDataBinder.java:133)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.bind(MultiActionController.java:540)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.invokeNamedMethod(MultiActionController.java:468)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.handleRequestInternal(MultiActionController.java:408)
	org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
	com.towertech.eec.filter.RequestFilter.doFilter(RequestFilter.java:64)
	org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:98)
root cause

org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'command' on field 'activityName': rejected value [12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901]; codes [lengthExceed.activityName.command.activityName,lengthExceed.activityName.activityName,lengthExceed.activityName.java.lang.String,lengthExceed.activityName]; arguments []; default message [null]
	org.springframework.web.bind.ServletRequestDataBinder.closeNoCatch(ServletRequestDataBinder.java:135)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.bind(MultiActionController.java:540)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.invokeNamedMethod(MultiActionController.java:468)
	org.springframework.web.servlet.mvc.multiaction.MultiActionController.handleRequestInternal(MultiActionController.java:408)
	org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153)
	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
	com.towertech.eec.filter.RequestFilter.doFilter(RequestFilter.java:64)
	org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.java:98)
thank you in advance