I am working an application which was developed on struts frame work.When i deploy and run the application, occasionally i used to get Null Pointer Exception after i login into that page.when i check the log file i used to get "struts-config" must match "(data-sources?,form-beans?,global-exceptions?,global-forwards?,action-mappings?,controller?,message-resources*,plug-in*).Is this error because of the version of struts config file does not match and it does not have a doc type tag in struts config file.