I got a lot of warning messages for all xml files under META-INF and WEB-INF:
The file cannot be validated as there was a connection problem.

for such as code
<!DOCTYPE jboss PUBLIC "-//JBoss//DTD JBOSS 3.0//EN" "http://www.jboss.org/j2ee/dtd/jboss_3_0.dtd">

This codes are generated by XDoclet.

How to solve this issue? Any affection for application to run?