NoClassDefFoundError if servlet isn't started right away

[Migrated From Jforum.net]

I've installed JForum as a way of gettng a bit of feedback about my site, http://wow.gedsguides.com/, not that anyone seems to be bothering.

Anyway, it installed OK but there are a couple of problems.

The first, small problem, is when I restart Tomcat, if I don't immediately open the home page for the forums (http://www.gedsguides.com/forums/forums/list.page) then it won't start properly on demand later. I haven't tested how long I have to leave it before this happens, but it's no more than a couple of hours. If I do open a window right away, everything seems to work fine.

Second, more serious thing, is that it's started going wrong now after about 12-24 hours or so, and when I visit the page I get this:

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Servlet.init() for servlet jforum threw exception
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.valves.FastCommonAccessLogValve.invoke(FastCommonAccessLogValve.java:481)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:526)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:307)
org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:385)
org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:748)
org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:678)
org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:871)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Thread.java:595)

root cause

java.lang.NoClassDefFoundError
net.jforum.C3P0PooledConnection.init(C3P0PooledConnection.java:64)
net.jforum.ForumStartup.startDatabase(ForumStartup.java:75)
net.jforum.JForum.init(JForum.java:93)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
org.apache.catalina.valves.FastCommonAccessLogValve.invoke(FastCommonAccessLogValve.java:481)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:526)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:307)
org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:385)
org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:748)
org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:678)
org.apache.jk.common.SocketConnection.runIt(ChannelSocket.java:871)
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
java.lang.Thread.run(Thread.java:595)



My ISP is running Tomcat 5.5.9 on JDK 1.5.0.

Hmm, actually I've just noticed that someone - possibly me - has set it to restart tomcat automatically every 24 hours, in which case problem #2 is probably the same as problem #1 .

I suppose I could get over this by setting the servlet to be started automatically rather than on-demand, and I will as a last resort, but initially I'd prefer to know what's going wrong.

[originally posted on jforum.net by gedsguides]

[Migrated From Jforum.net]

Man, that's really crazy.

Yeah, you can configure the servlet so it start automatically.

Rafael
[originally posted on jforum.net by Rafael Steil]

[Migrated From Jforum.net]

I have install it many times, it the same problem.
It seems can install well, but when i open the first pages, (http://www.loveworldfriend.com/JForum-2.1.6/forums/list.page)
it is here:


java.lang.NoClassDefFoundError
at net.jforum.C3P0PooledConnection.init(C3P0PooledConnection.java:64)
at net.jforum.ForumStartup.startDatabase(ForumStartup.java:75)
at net.jforum.JForum.init(JForum.java:93)
at com.caucho.server.http.Application.createServlet(Application.java:3114)
at com.caucho.server.http.Application.loadServlet(Application.java:3065)
at com.caucho.server.http.QServletConfig.loadServlet(QServletConfig.java:435)
at com.caucho.server.http.Application.getFilterChainServlet(Application.java:2809)
at com.caucho.server.http.Application.buildFilterChain(Application.java:2765)
at com.caucho.server.http.Invocation.service(Invocation.java:313)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
at java.lang.Thread.run(Thread.java:595)


[originally posted on jforum.net by kevin]

[Migrated From Jforum.net]

Given that I'm not the only one getting this error, I'd say this is a real, solid bug. I have to say it doesn't do JForum any favours when I look at my forums and see that they are down yet again, same old problem. Thank god they aren't getting any traffic ((

kevin wrote:I have install it many times, it the same problem.
It seems can install well, but when i open the first pages, (http://www.loveworldfriend.com/JForum-2.1.6/forums/list.page)
it is here:


java.lang.NoClassDefFoundError
at net.jforum.C3P0PooledConnection.init(C3P0PooledConnection.java:64)
at net.jforum.ForumStartup.startDatabase(ForumStartup.java:75)
at net.jforum.JForum.init(JForum.java:93)
at com.caucho.server.http.Application.createServlet(Application.java:3114)
at com.caucho.server.http.Application.loadServlet(Application.java:3065)
at com.caucho.server.http.QServletConfig.loadServlet(QServletConfig.java:435)
at com.caucho.server.http.Application.getFilterChainServlet(Application.java:2809)
at com.caucho.server.http.Application.buildFilterChain(Application.java:2765)
at com.caucho.server.http.Invocation.service(Invocation.java:313)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
at java.lang.Thread.run(Thread.java:595)

[originally posted on jforum.net by gedsguides]

[Migrated From Jforum.net]

Looked at the code lines around the section causing the problem and it seems like it's related to your JDBC driver.

One thing to make sure of is that the JDBC driver jar is not located in multiple Tomcat lib levels (e.g. common/shared/webapp). TC has strict class loader security rules. This means that if the JDBC layer and same driver has been initialized at the Common level, a call by a Webapp can not replace the Common level class with the Webapp level class (A trojan webapp could use this to hijack the server if it was allowed).

A quick test of this would be to remove the JDBC driver from your webapp lib directory and see if jForum still works.

FWIW, a common cause having the same JDBC driver loaded at a higher level, this is that another webapp is using a JNDI datasource or Tomcat security is using a DataSourceRealm.

If that's not the case, try adding a <load-on-startup>1</load-on-startup> node to the Jforum servlet in your web.xml to force it to start when TC is restarted. Make sure to remove the Installer servlet (see: https://coderanch.com/t/576919 #14222)

Hope this helps.

Greg
[originally posted on jforum.net by monroe]