Inside Tomcat's default web.xml file (CATALINA_HOME/conf/web.xml) there is a servlet declaration for the "jsp" servlet (which is used to process JSP's).
If you set a servlet parameter named classdebuginfo to true, Tomcat will include debug info.

Following is Tomcat's default declaration with the classdebuginfo parameter added:

<servlet>
  <servlet-name>jsp</servlet-name>
  <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
  <init-param>
    <param-name>classdebuginfo</param-name>
    <param-value>true</param-value>
  </init-param>
  <init-param>
    <param-name>logVerbosityLevel</param-name>
    <param-value>WARNING</param-value>
  </init-param>
  <load-on-startup>3</load-on-startup>
</servlet>