Debugging FAQs

+ +

How do I debug Cocoon using JDK1.3+?

With JDK1.3 or above, first set the CATALINA_OPTS (for Tomcat 4.x as +shown below (on Win2K).

set CATALINA_OPTS=-server -Xdebug -Xnoagent -Djava.compiler=NONE
+    -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000
+

Note

For Tomcat 3.x the param is TOMCAT_OPTS and the first value is +-classic instead of -server.

Add it to the catalina.bat, that can be found in +%TOMCAT_HOME%\bin\, right after the first rem section.
+The same information in more detail can be found at +Setting up Tomcat +for Remote Debugging.

The problem of this approach is the blocking of using Tomcat in another mode. +You always have to touch catalina.bat again when changing the mode and +this file is really a batch beast, isn't it? Furthermore catalina.bat +is only a starting mode library and should not be touched by hand IMO.
+Let me propose my approach: Go to the last line of startup.bat where +catalina.bat is called. Replace

call "%EXECUTABLE%" start %CMD_LINE_ARGS%

with

set JPDA_TRANSPORT=dt_socket
+set JPDA_ADDRESS=8000
+call "%EXECUTABLE%" jpda start %CMD_LINE_ARGS%
+

A switch can now be done by adding and removing jpda. You can also +place the old line in comments and switch between them. Or you copy +startup.bat to debug.bat and do the changes there.

Note

Note that Tomcat must be started using startup.bat in +order to set these values; if you are using "java.exe -jar ...bootstrap.jar +start" or anything similar to start Tomcat, you have to set the +CATALINA_OPTS on the commandline or for Windows in general.

Note

If you use Jetty included with Cocoon 2.1 it's much easier. +Instead of doing "cocoon.bat servlet" you simply call "cocoon.bat +servlet-debug".

After having started Tomcat or the servlet container of your choice in remote +debugging mode, attach the debugger to localhost:8000 using "jdb -attach +myhost:8000". If you get an error "Error accessing shared memory, rc = +-1", try "jdb -connect com.sun.jdi.SocketAttach:port=8000" +instead.
+More information on this can be found in the + JPDA +documentation.

Note

The attaching of the debugger to that port can be done very +easily in almost all modern IDEs as Eclipse, IDEA, NetBeans or JBuilder. Mostly +port 8000 and dt_socket are preselected.

Now that I have prepared Tomcat and my IDE for debugging: How do I debug? +

Of course we can not give to many details here as it might be different for +all the possible IDEs out there, but the general proceeding should be the same. +The following steps are for jdb, it should be much easier for the IDEs.
+1. Set a breakpoint in a class via "stop in +org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.checkPipeline". +
+2. Enter a URL in your browser to get Cocoon to do the stuff that needs +debugging. When your breakpoint is hit, you'll get the message in jdb:
+ +Breakpoint hit: "thread=Thread-11", +org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.checkPipeline(), +line=363 bci=0.
+3. Use the debugger commands "print", "next", and "cont" to examine the data and +step through the code.

+Errors and Improvements? + If you see any errors or potential improvements in this document + please help us: + + View, Edit or comment on + the latest development version (registration required). +

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