Java web-app debugging not possible due to direct undeploy on debug

When i try to debug my webapp it starts up the tomcat server and the application, but shuts down the debugger shortly before the app gets usable. I see the debugging toolbar for a second before it vanishes again, though the app keeps running.

Tomcat-log:

Listening for transport dt_socket at address: 11555
23.03.2010 01:24:35 org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: .:/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java
23.03.2010 01:24:35 org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8084
23.03.2010 01:24:35 org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 847 ms
23.03.2010 01:24:35 org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
23.03.2010 01:24:35 org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.20
log4j:WARN No appenders could be found for logger (org.springframework.web.co开发者_开发知识库ntext.ContextLoader).
log4j:WARN Please initialize the log4j system properly.
23.03.2010 01:24:41 org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8084
23.03.2010 01:24:41 org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
23.03.2010 01:24:41 org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/78  config=null
23.03.2010 01:24:41 org.apache.catalina.startup.Catalina start
INFO: Server startup in 5855 ms
23.03.2010 01:24:42 org.apache.catalina.startup.HostConfig checkResources
INFO: Undeploying context []
23.03.2010 01:24:45 org.apache.catalina.core.StandardContext start
INFO: Container org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/] has already been started

Debugging log:

Attached JPDA debugger to localhost:11555
Checking data source definitions for missing JDBC drivers...
Deploying JDBC driver to /Applications/NetBeans/apache-tomcat-6.0.20/lib/mysql-connector-java-5.1.6-bin.jar
Stopping Tomcat process...
Waiting for Tomcat...
Tomcat server stopped.
Starting Tomcat process...
Waiting for Tomcat...
Tomcat server started.
Undeploying ...
OK - Undeployed application at context path /
In-place deployment at /path/to/project/dir/build/web
deploy?config=file%3A%2Fvar%2Ffolders%2FZP%2FZPbqxGrbHFaUlXzAfgWV1%2B%2B%2B%2BTQ%2F-Tmp-%2Fcontext734173871283203218.xml&path=/
OK - Deployed application at context path /
start?path=/
Start is in progress...
OK - Started application at context path /
debug-display-browser:
Browsing: http://localhost:8084/
connect-client-debugger:
BUILD SUCCESSFUL (total time: 18 seconds)

System is Netbeans 6.8 on MacOS 10.6.2.

You should see if the TC server is still in debug mode. The easiest way to do that is to Debug->Attach Debugger to localhost;11555. If it is still running 'debuggable', you will be able to do a fair bit of debugging that way.

I had similar problem where debugging started but kind of stopped immediately. The application was deployed however. I was not even able to attach to debugger manually, even if the Tomcat was running in debug mode. By creating a simple debuggable hello world project and starting debugging it also made debugger to break to my "problem project"'s break points as well.. But this was not really way to work.

My problem was "solved" by dropping mysql-connector-java.jar from my web project. I don't see any reasoning, but it simply works now. FYI also, the Netbean's Tomcat config's property "Enable JDBC driver deployment" did not have effect.

My environment was Netbeans 6.9.1 and project type was maven2, run on on Win7.