source/core-developers/debugging.md

---
layout: core-developers
title: Debugging
---

# Debugging

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

The [Debugging Interceptor](debugging-interceptor.html) 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 [struts.properties](struts-properties.html) file or `struts.xml` file, like:

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

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

```xml
<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](http://ietab.mozdev.org/).

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