ClassNotFoundException with ServletContextlistener

Question

I get an exception whenever I try getting context parameter from we.XML into a ServletContextListener class, I am really having hard times understanding why It is not working, here's the exception in Apache Tomcat 7.0.11 log :

 Oct 21, 2011 1:24:23 PM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Error configuring application listener of class alaa.ServletContextListener
java.lang.ClassNotFoundException: alaa.ServletContextListener
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
at   
   org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:415)
at      

at    org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:118)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4618)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5184)
at org.apache.catalina.core.StandardContext$1.call(StandardContext.java:5179)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)

Here's a part of my web.xml :

 <context-param>
    <param-name>catName</param-name>
    <param-value>meshmesh</param-value>
</context-param>
<context-param>
    <param-name>catBreed</param-name>
    <param-value>egyptian</param-value>
</context-param>  
<listener>
   <listener-class>alaa.CatLisenter</listener-class>
</listener>
<session-config>
      <session-timeout>
        30
      </session-timeout>
</session-config>

Here's my ServletContextListener.java:

package alaa;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class CatLisenter implements ServletContextListener {

@Override
public void contextInitialized(ServletContextEvent sce) {
    ServletContext sc = sce.getServletContext();
    String name = sc.getInitParameter("catName");

    String breed = sc.getInitParameter("catBreed");

    Cat maCat = new Cat();
    maCat.setName(name);
    maCat.setBreed(breed);

    sc.setAttribute("cat", maCat);
}

@Override
public void contextDestroyed(ServletContextEvent sce) {
    throw new UnsupportedOperationException("Not supported yet.");
}   
}



Here's Cat.java : 





package alaa;

public class Cat {
private String name;
private String breed;


public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getBreed() {
    return breed;
}


public void setBreed(String breed) {
    this.breed = breed;
}
 }

many thanks

Are you sure your listener is being deployed?

Dave Newton
– Dave Newton

2011-10-21 13:19:04 +00:00
Commented Oct 21, 2011 at 13:19 — Dave Newton
– Dave Newton, Commented Oct 21, 2011 at 13:19

Lauro Caetano · Accepted Answer · 2011-10-21 13:14:16Z

10

Try to clear the tomcat work directory and clean. After that, publish your project and run again.

answered Oct 21, 2011 at 13:14

Lauro Caetano

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1 Comment

Rehme Over a year ago

I did as you told me to, deleted context file from \Apache Tomcat 7.0.11\conf and ran my webApp again, and It worked just perfect, thanks a million .

Arjan Tijms · Accepted Answer · 2013-04-29 06:55:40Z

5

My guess is that you have packaged the servlet-api jar in your webapp (in the WEB-INF/lib) folder and this is causing conflicts since the servlet-api will already be present in the container. Make sure you don't include any servlet-api or jsp-api (or Java EE api) jars in your webapp when you deploy it.

edited Apr 29, 2013 at 6:55

Arjan Tijms

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answered Oct 21, 2011 at 12:43

pap

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4 Comments

Rehme Over a year ago

Did not create any servlet or jsp page yet, Is this what you meant ? I'm figuring on creating a servlet so that I could get ServletContext attribute then get the cat instances back .

pap Over a year ago

@RealSilhouette no, that's not what I meant. The final build that you are deploying to tomcat, does it include any jar-files in the WEB-INF/lib directory called something like servlet-api.jar or jsp-api.jar? If so, you are not packaging your war correctly as those jars already exist in the tomcat container, causing conflicts. How are you building? Maven? Through the IDE?

Dave Newton Over a year ago

Where is there a conflict? It says the listener class isn't found (assuming my phone is displaying everything correctly :(

Rehme Over a year ago

@pap the WEB-INF/lib directory does not has any jar-files

Celia · Accepted Answer · 2014-08-21 11:50:27Z

1

I had the same problem running JUnit in a Tomcat 7 environment and I solved it adding a dependency in maven (pom.xml) like this:

    <dependency>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>tomcat-servlet-api</artifactId>
        <version>7.0.54</version>
        <scope>provided</scope>
    </dependency>

answered Aug 21, 2014 at 11:50

Celia

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Comments

Rama Krishna · Accepted Answer · 2016-07-08 06:18:18Z

1

If you are working in Eclipse, Then just clean your project.

Follow this simple step, Go to Project > clean...> clean all projects > Ok

answered Jul 8, 2016 at 6:18

Rama Krishna

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Comments

gauti · Accepted Answer · 2015-06-05 06:30:45Z

0

I had the same issue when I tried with eclipse LUNA version and tomcat 7. The same code without any extra changes worked in eclipse JUNO with tomcat 7.

answered Jun 5, 2015 at 6:30

gauti

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Comments

Emir Marques · Accepted Answer · 2016-05-04 18:19:00Z

0

Verify the space in disk. When eclipse copy the folder libs if not space in disk this error may occur

answered May 4, 2016 at 18:19

Emir Marques

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George Kibira · Accepted Answer · 2022-02-03 13:46:23Z

0

I had a similar problem. It Maybe not be related to what you had but it might save someone some time. I had my listener-class wrong in the web descriptor file:)

answered Feb 3, 2022 at 13:46

George Kibira

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OSEMA TOUATI · Accepted Answer · 2023-10-13 14:58:05Z

0

I had similar problem, the previous solutions didn't work for me.
It was simpler in my case, tomcat wasn't bound to my app (I used eclipse).

To solve this try the following as it may work for you:
In Project > Properties > Java build path > Libraries look for Server Runtime, and bind a tomcat server to your project (go ahead and add tomcat server to your eclipse project if you didn't already have).

This fixed my issue.

answered Oct 13, 2023 at 14:58

OSEMA TOUATI

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