<< back to Core Developers Guide Edit on GitHub

# Debugging

Modern IDEs provide excellent support for debugging. In addition, the framework provides support for inspecting framework-specific objects at runtime.

The Debugging Interceptor provides three debugging modes to provide insight into the data behind the page. The `xml` mode formats relevant framework objects as an XML document. The `console` mode provides a OGNL command line that accepts entry of runtime expressions, and the `browser` mode adds an interactive page that display objects from the Value Stack.

To use the debugging, first be sure that `struts.devMode` is set to `true` is enabled through the default.properties file or `struts.xml` file, like:

    <constant name="struts.devMode" value="true" />

Then, whenever a page needs debugging, add `?debug=xml` or `?debug=console` or `?debug=browser` to the URL.

    <debug>
         <parameters />
         <context>
            <struts.actionMapping>
            <class>class org.apache.struts2.dispatcher.mapper.ActionMapping</class>
            <name>showcase</name>
            <namespace>/</namespace>
            </struts.actionMapping>
            <attr />
            <__devMode>true</__devMode>
            <report.conversion.errors>false</report.conversion.errors>
        </context>
        <request />
        <session />
        <valueStack>
            <value>
                <actionErrors />
                <actionMessages />
                <class>class com.opensymphony.xwork2.ActionSupport</class>
                <errorMessages />
                <errors />
                <fieldErrors />
                <locale>
                    <ISO3Country>USA</ISO3Country>
                    <ISO3Language>eng</ISO3Language>
                    <class>class java.util.Locale</class>
                    <country>US</country>
                    <displayCountry>United States</displayCountry>
                    <displayLanguage>English</displayLanguage>
                    <displayName>English (United States)</displayName>
                    <displayVariant />
                    <language>en</language>
                    <variant />
                </locale>
            </value>
            <value>
                <class>class com.opensymphony.xwork2.DefaultTextProvider</class>
            </value>
        </valueStack>
    </debug>

For `?debug=xml` use Internet Explorer or an IE tab in FireFox.

For `?debug=console` you may need to relax any popup blockers.