HttpServlet not found?
Hi,
I get an NoClassDefFoundError, when I try to access a servlet. I compiled it with "javac -cp /home/tomcat/j2ee/lib/j2ee.jar:/home/tomcat/mysql MyServlet.java". this displays no error.
But I can't access the servlet. it shows me that:
exception
javax.servlet.ServletException: Error allocating a servlet instance
root cause
java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet
all that happens only in one "webapps"-dircetory, all others are working fine. Even when I copy one servlet from another "webapp" to it, I get that error.
Do you have anything like servlet-api.jar in your web-inf/lib directory? Or a jar file containing any of the Servlet classes?That could potentially throw a spanner in the works for that one web app.
No, there aren't. I don't have the directory "lib" and there's no jar-file.Can be something wrong with my $CLASSPATH? I haven't set it yet.
You should have a servlet-api.jar in the $TOMCAT_HOME/common/lib directory IIRC. It contains the servlet api. You could also check if the j2ee.jar you specified for compilation exists (and has the necessary classes).
Actually, you should not be using the j2ee.jar in your case. Use the servlet-api.jar provided with Tomcat.
that doesn't work. I get the same error as with j2ee.jar.Rarely, really rarely it works, but when I compile my source, without any changes, again, it doesn't work.
Please use servlet-api.jar which is bundled with tomcat in the classpath: egjavac -classpath /home/tomcat/servlet-api.jar /home/tomcat/mysql/MyServlet.java
can somebody help?i installed apache-tomcat 5.5.12 on linux.when i run the url for the servlet, error 404 appears.. requested url not found on this server.. can u tell me how to overcome this?thanksjade
Jadea at 2007-7-16 13:14:35 >
Did I type "j2ee.jar"? I meant servlet-api.jar, sorry.Can be something wrong with the startup-script of tomcat?
1. What is your deployment directory Structure?2. Did your compilation cause error?3. What is inside your tomcat-server logs4. Did you import javax.*..*HttpServlet* in your sourcefile?5. How are your trying to access it?
1. I don't know, what you mean with "deployment directory". I guess it's the webapp-directory. Right? The structure of that is:
db
--WEB-INF
--web.xml
--classes
Servlet.java
Servlet.class
2. No, it doesn't
3. You can finde the whole entry for it [url=http://nopaste.debianforum.de/1705]here[/url]
4. I import it with
import javax.servlet.http.*;
5. My servlet? With "http://localhost:808/db/phone (I entered "phone" in web.xml as servlet-mapping)
Your servlet needs to be in a package.
As of Java 1.4, classes in the "unnamed" packaged are not accessible.
So your java file should be in
/WEB-INF/classes/mypackage/Servlet.java
Your web.xml file would need to be updated to match the new full class/package name.
However that doesn't explain your original error message.
Try compiling it from the WEB-INF/classes directory.with
"javac -cp .;/home/tomcat/common/lib/servlet-api.jar;/home/tomcat/mysql mypackage.MyServlet.java".
The error indicate that your class file is not found by servlet container. I guess your directory structure looks kinda weird. What you need to do is
1. replace db with Servlets
2. create a package "test" and store your file under $CATALINA_HOME/webapps/Servlets/WEB-INF/classes/test/Servlet.java
3. Edit your web.xml
<servlet>
<servlet-name>Servlet</servlet-name>
<servlet-class>test.Servlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Servlet</servlet-name>
<url-pattern>*.try</url-pattern>
</servlet-mapping>
4. Access by http://localhost:8080/Servlets/first.try
That should work
OK, I found the problem: When I started my tomcat-server with something like "path/dirs/startup.sh" I got that error.
Now, when I start it with "cd path/dirs/; ./startup.sh" It works just fine. Don't know why.
BTW: why do I have to use packages? It also works fine without any packages. I use JDK 1.5
I encounter the same problem.
I have tested that put the class into a package is useless.
I defined one servet in package and another none. if I restart tomcat with full path like "/usr/local/apache-tomcat-5.5.20/bin/shutdown.sh && /usr/local/apache-tomcat-5.5.20/bin/startup.sh " , tomcat will throw the error , HttpServlet not found. But if I do a restart with " cd /usr/local/apache-tomcat-5.5.20/ && ./shutdown.sh && ./startup.sh" ,
everything will work fine.
If somebody can teach us what is class loading ?
