STRUTS2 Validator Specification Error resolution

The configuration file header for the Struts2 validator today has an error, as follows:

<! DOCTYPE validators Public
"-//opensymphony group//xwork Validator 1.0.2//en"
"Http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd" >

The error message is as follows:

Referenced file contains errors (HTTP://WWW.OPENSYMPHONY.COM/XWORK/XWORK-VALIDATOR-1.0.2.DTD). For more information, right click on the Problems
View and select "Show Details ..."

Check the Internet, because HTTP://WWW.OPENSYMPHONY.COM/XWORK/XWORK-VALIDATOR-1.0.2.DTD is not a DTD constraint file, open the Web site, found that Opensymphony's web site has moved away , because xwork things have been incorporated into the struts2 and become part of Apache. All the DTDs have been handed over to http://struts.apache.org/dtds/this place.

      after the struts2 of the specification of the validator to be changed to:
<?xml version= "1.0" encoding= "UTF-8"
<! DOCTYPE validators Public "-//apache struts//xwork Validator 1.0.2//en" "http://struts.apache.org/dtds/ XWORK-VALIDATOR-1.0.2.DTD
       So there will be no error, normal operation.