Parse error in application web.xml

[Jimmy Tommy]

Hello everyone.

I am using an application on my Tomcat server and I got below error in catalina logs. WWW site is not working. What could be the problem here? Thanks.

01-Dec-2022 12:37:26.257 SEVERE [localhost-startStop-1] org.apache.tomcat.util.descriptor.web.WebXmlParser.parseWebXml Parse error in application web.xml file at [file:/D:/Program%20Files/Apache%20Software%20Foundation/Tomcat%208.5/webapps/bdmsimulationservice/WEB-INF/web.xml]

My web.xml looks like this:


<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xmlns="http://java.sun.com/xml/ns/javaee"         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"         id="WebApp_ID" version="2.5"         metadata-complete="true"> <display-name>Bdm Simulation Service</display-name> <!--SERVLETS--> <servlet> <display-name>BdmSimulationServlet</display-name> <servlet-name>BdmSimulationServlet</servlet-name> <servlet-class>com.app-name.servlet.BdmSimulationServlet</servlet-class> </servlet> <servlet> <display-name>BdmHealthzServlet</display-name> <servlet-name>BdmHealthzServlet</servlet-name> <servlet-class>com.app-name.infrastructure.health.HealthzServlet</servlet-class> </servlet> <!--SERVLET MAPPING--> <servlet-mapping> <servlet-name>BdmSimulationServlet</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>BdmHealthzServlet</servlet-name> <url-pattern>/healthz</url-pattern> </servlet-mapping> <!--LISTENER--> <listener> <listener-class>com.app-name.servlet.BdmSimulationServletInitializationListener</listener-class> </listener> </web-app>

[Himai Minh]

In your IDE, does it highlight any error in your web.xml? I took a quick look and don't see anything wrong with your web.xml.

[Himai Minh]

One more thing. Can this older post help :
https://coderanch.com/t/689115/application-servers/start-Java-servlet-Tomcat  ?

[Stephan van Hulst]

app-name is not a valid package name. I assume you changed it before you posted it here, but I'm just checking.

Just to be sure, did you share webapps/bdmsimulationservice/WEB-INF/web.xml with us, or the version inside your project directory. Please share the Tomcat version with us.

[Ron McLeod]

Jimmy Tommy wrote:01-Dec-2022 12:37:26.257 SEVERE [localhost-startStop-1] org.apache.tomcat.util.descriptor.web.WebXmlParser.parseWebXml Parse error in application web.xml file at [file:/D:/Program%20Files/Apache%20Software%20Foundation/Tomcat%208.5/webapps/bdmsimulationservice/WEB-INF/web.xml]

Was there more included in the error message, like a line number or hints as to what caused the parse error?

[Tim Holloway]

Stephan van Hulst wrote:app-name is not a valid package name. I assume you changed it before you posted it here, but I'm just checking.

Just to be sure, did you share webapps/bdmsimulationservice/WEB-INF/web.xml with us, or the version inside your project directory. Please share the Tomcat version with us.

Actually, that's not true. You can have hyphens in a package name component, and it's actually more legitimate than putting capital letters in a package name component. Though I'd still recommend avoiding it.

I pulled a copy of that file into my Eclipse IDE and the Eclipse XML plugin whined about all sorts of stuff. Yet, the errors it gave were bogus and I could not spot anything legitimately wrong myself.

My best guess is that the file was created from a word-processor like app and that it has non-ASCII characters in it that look like legitimate ASCII (yes, web.xml is actually UTF-8, but only the "ASCII" characters are generally used). Either that or there's something not quite right in the attributes of the web-inf header element.

So I'm puzzled and am looking forward to someone being able to crack this mystery.

[Ron McLeod]

Tim Holloway wrote:... You can have hyphens in a package name component

I'm not sure if that is permitted or not, but when creating a package name based on an Internet domain name, the JLS suggests using an underscore where a hyphen is found:

The first component of a unique package name is always written in all-lowercase ASCII letters and should be one of the top level domain names, such as com, edu, gov, mil, net, or org, or one of the English two-letter codes identifying countries as specified in ISO Standard 3166.

In some cases, the Internet domain name may not be a valid package name. Here are some suggested conventions for dealing with these situations:

  - If the domain name contains a hyphen, or any other special character not allowed in an identifier (§3.8), convert it into an underscore.

  - If any of the resulting package name components are keywords (§3.9), append an underscore to them.

  - If any of the resulting package name components start with a digit, or any other character that is not allowed as an initial character of an identifier, have an underscore prefixed to the component.

[Tim Holloway]

When id doubt, check it out. Eclipse did indeed fail a hyphen in package name component. I'm not sure that was always the case, since I'm thinking (or at least hallucinating) that at least one major open-source library had hyphens in package name components. But apparently, no more.

TLDs are problematic, since the explosion (.info, .sale, whatever) and academic projects definitely allow creativity. Though I recommend using the school and course ID as parts of the package path. However some schools are better known as ".com"s or ".org"s as ".edu"s. It was fairly easy to grab a domain name back in the olden days, and of course, a lot of institutions have the same initials.