I am getting this NullPointer Exception :
java.lang.NullPointerException at org.apache.struts.validator.Resources.getMessageResources(Resources.java:127) at org.apache.struts.validator.Resources.getActionMessage(Resources.java:349) at org.apache.struts.validator.FieldChecks.validateMask(FieldChecks.java:241) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:324) at org.apache.commons.validator.ValidatorAction.executeValidationMethod(ValidatorAction.java:543) at org.apache.commons.validator.Field.validateForRule(Field.java:766) at org.apache.commons.validator.Field.validate(Field.java:845) at org.apache.commons.validator.Form.validate(Form.java:290) at org.apache.commons.validator.Validator.validate(Validator.java:353) at com.tietoenator.dk.lub.utility.PropertyValidator.validate(PropertyValidator.java:189) My validation.xml entry lookes like this : <form name="courseStatusViewActionForm"> <field property="completedDate" depends="mask"> <msg name="mask" key="errors.courseStatusViewActionForm.date.maskmsg"/> <arg0 key="courseStatusViewActionForm.completedDate"/> <var> <var-name>mask</var-name> <var-value>${date}</var-value> </var> </field> </form> I got these in my resourse bundle : errors.courseStatusViewActionForm.date.maskmsg=Gennemført dato er ikke valid. courseStatusViewActionForm.completedDate=gennemført dato Med venlig hilsen / Kind regards Kristian Lind Petersen Konsulent / Consultant TietoEnator A/S Rygaards Alle 131 DK - 2900 Hellerup Telephone: +45 72 30 60 00 Mobile: +45 25 42 36 56 E-mail: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>