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Validate your Wicket markup without pain

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This project validates the output of your Apache Wicket application while running. It includes a error view showing each validation error, with line-precise error messages.

Validates the following w3c standards:

This project includes the HTML validator taken from html validator.


Make sure you use Wicket 1.5. This validator does not run on Wicket 1.4 or earlier. Java 6 is also a minimum requirement.

There is no release available at this time. You have to build a version locally yourself (using Apache Maven.

Add the Wicket Stuff validator to your POM as a dependency:


Depending on your setup you need to use a different scope (for example test or provided to prevent the validator to be deployed to production).

Add the following lines to your Application's init method:

protected void init() {
    getRequestCycleSettings().addResponseFilter(new HtmlValidationResponseFilter());

You might want to put a check for the configuration of your application around the addition of the response filter, to ensure that the filter doesn't run in production mode:

if (RuntimeConfigurationType.DEVELOPMENT == getConfigurationType()) {
    getRequestCycleSettings().addResponseFilter(new HtmlValidationResponseFilter());


Building Wicket.Validator is not difficult: you need to have Java 6 and Maven 3 installed, and know how to checkout sources from github. Assuming you know how to use Git, you need to do the following on a command prompt:

$ git clone git://
$ cd wicket-stuff-markup-validator
$ mvn install

Then you can add the Wicket.Validator dependency to your own application using Maven.


In order to make this work, we had to provide jar files of several open source projects required by the HTML validator code:

Since these recent releases are not available from the central Maven repository, we included the sources and provide the jar files in our own namespace (the package names are unmodified).