NoClassDefFound error

[flowcontrol]

I'm coming back to a project after not working on it for several weeks. I created a new servlet for my web-app and "registered" it in the app's deployment descriptor. I reloaded the app using Tomcat Manager. When I try to invoke the servlet, I get a NoClassDefFound exception. The class exists, so I'm thinking that maybe two different class loaders are involved and thus one class can't find the other. But, that's just a WAG. I was running tomcat with -Dsecurity.manager when the error occurred, but I took that out (and still get the error). Does anybody have ANY ideas??

Here is part of the error message:

[b]exception[/b]

javax.servlet.ServletException: Error allocating a servlet instance
     org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
...

[b]root cause[/b]

java.lang.NoClassDefFoundError: com/mycompany/dept/MyStats (wrong name: MyStats)
     java.lang.ClassLoader.defineClass0(Native Method)
     java.lang.ClassLoader.defineClass(ClassLoader.java:539)
     java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)

Here is the deployment descriptor (I used different tokens for servlet-name, servlet-class, and servlet-mapping to make it clear what the error message was referring to):

<servlet>
   <servlet-name>
      Stats
   </servlet-name>
   <servlet-class>
      com.mycompany.dept.MyStats
   </servlet-class>
</servlet>

<servlet-mapping>
   <servlet-name>
      Stats
   </servlet-name>
   <url-pattern>
      /GetStats
   </url-pattern>
</servlet-mapping>

 

[sedj]

Sounds like your package names are incorrect at compile time - its not tomcat.

com/mycompany/dept/MyStats (wrong name: MyStats)

Make sure that when you compile MyStats.java it is in the correct directory structure (ie com/mycompany/dept) and that you compile it as :

javac com/mycompany/dept/MyStats.java

and that the code has the correct package declaration , ie

package com.mycompany.dept;

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[flowcontrol]

You're right on the mark. I figured it out eventually. Java 2 does not allow classes in the default package to be imported. I had failed to put a package declaration at the top of the file.

Sheesh! How could I have forgotten that?

Thanks sedj!