What does offending class tell me on server startup?

Question

I'm having the jee7 web api as dependency. I can start my app on tomcat application successfully, but what does the following "offending class" statements tell me? Do I have to take any actions?

Jan 13, 2014 5:47:47 PM org.apache.catalina.loader.WebappClassLoader validateJarFile
Information: validateJarFile(C:\Users\me\Servers\apache-tomcat-7.0.50\wtpwebapps\app\WEB-INF\lib\el-api-2.2.jar) - jar not loaded. See Servlet Spec 3.0, section 10.7.2. Offending class: javax/el/Expression.class
Jan 13, 2014 5:47:47 PM org.apache.catalina.loader.WebappClassLoader validateJarFile
Information: validateJarFile(C:\Users\me\Servers\apache-tomcat-7.0.50\wtpwebapps\app\WEB-INF\lib\javaee-web-api-7.0.jar) - jar not loaded. See Servlet Spec 3.0, section 10.7.2. Offending class: javax/servlet/Servlet.class

pom.xml

    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-web-api</artifactId>
        <version>7.0</version>
    </dependency>

Answer 1

It seems like you (your Servlet container) are trying to load some classes that have already been loaded. The servlet-api and el-api should be provided by the Servlet container.

Change your pom.xml to account for that

<dependency>
    <groupId>javax</groupId>
    <artifactId>javaee-web-api</artifactId>
    <version>7.0</version>
    <scope>provided</scope>
</dependency>

Answer 2

I have faced the same issue during a project using Eclipse.

Doing below things resolved the issue

1. Added javax.*.jar to the build path
2. Removed the project - gave clean build and add the project and finally published....!!

Bingo...!!

This resolved my issue. Hope this helps.

Thanks,

mskr.

Answer 3

This is a very common problem for developers who are using Maven as a build tool. when , we include the servlet-api as a project dependency i.e pom.xml like this :

<dependency>
<groupId>  javax.servlet</groupId>

<artifactId>servlet-api</artifactId>
<version>2.5</version>

add scope as provided in the above dependency as following .

<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>