Before you write to the Tomcat list asking for help with a problem, there are a number of basic troubleshooting steps you should take. Please note that these steps are just basic steps, more advanced troubleshooting is covered in other chapters along with the topics it is useful for.

In the server.xml file we saw three logs. They can each take a verbosityLevel parameter. If you are having trouble, set that to DEBUG and watch the logs for more information. Remember that there are three logs for three different reasons. Watch the log relevant to you - if you have no JSPs then there is no point watching the JASPER_LOG.

ServletError 500. If you find that you are getting these errors, read the stack trace. You should look through the stack trace for any of your classes. If there are some of your classes in the stack trace, then look at the lines of code where the errors occur. The most important part about troubleshooting is to determine if it is a code problem or a configuration problem. Inspecting the stack trace and associated code should help you make this decision.

Unable to compile JSP. If you get this error you will typically get a lengthy stack trace that doesn't make a lot of sense to you. The best thing to do is look on the far end of the first line. Here you should find the real problem. Think about what is happening when your JSP is being compiled. If you are using tag libraries (see Chapter XXX) then you should also consult the documentation with the taglib.