Debug inner class in JSP in Intellij Idea

Question

Can I debug into inner class in JSP ?

my application server is tomcat, and I am using Intellij Idea.

normal breakpoint in jsp is ok, but breakpoint in InnerClass not work.

in my test jsp code:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java.io.IOException" %>
<%
    new InnerClass().method_in_inner_class(out);
%>
<%!
    class InnerClass {
        void method_in_inner_class(JspWriter out) throws IOException {
            //set breakpoint under this line
            out.print("test1");
        }
    }
%>

In above jsp file, I set breakpoint at "out.print("test1");" but it NOT break at the line.

How can i debugging into the InnerClass ? thanks.

Answer 1

Your code seems to be allright, except for the fact that the second breakpoint wouldn't work either because the method is only called from method_in_inner_class. The problem is that debugging JSPs is a bit tricky, because you're not debugging a Java class.

Check if your server is compatible with debugging according to JSR45.

If it is, make sure that you have configured your IDE and server correctly:

For JSP debugging in Intellij there are some configurations that must be in order. The fact that Intellij always allows you to add a breakpoint on a JSP line does not necessarily imply that you’ve configured JSP debugging. In the following I refer to Intellij 8 configuration, w.r.t. previous versions you will need to do similar operations as the concepts are the same.

In order to enable JSP debugging you must do two steps: set a web application configuration in your project and add a web application server configuration.

Web application Configuration: in order to have JSP debugging, you must have a “web” facet in your project structure, pointing to the correct web.xml file. Depending on the kind of web application structure you are using, the facet may be detected automatically by Intellij (go anyway to check what it has done) or you may have to add it manually. Remember in the “Java EE build settings” tab to set as anable “Create web facet exploded directory”; if you don’t want duplications, a trick is just to enable it and point to your already existing directory.

(Web) Application server: Go to “edit configurations”, there you have to add to configurations an application server, not launch the web server as an application like any other. In this way Intellij will be able to intercept JSP calls. In the list of application servers, you should have the default one, Tomcat. Be sure to have a local Tomcat installation before you do this, and point to that when adding the web application server. The last trick is going to the “Deployment” tab and selecting as “Deployment source” the same facet that you configured in the previous step.

The same configuration works if you want to use another web application server, I tested it with the latest Caucho Resin releases and debugging works fine (it didn’t with the previous Intellij and Resin combinations).

If you don’t see Tomcat in the list of available application servers to add, check the plugins in the general Intellij settings pane: in the latest releases, more and more functionality has become “pluggable”, and even very basic functions may be disabled; this plugin is called “Tomcat integration”.

Finally, it is surely not true that JSP files need to be under WEB-INF to be under debugging.

Source: JSP debugging in IntelliJ IDEA

Also here might be some interesting configuration for you, if you haven't done it all ready.