Page History

...

@SupportsInformalParameters
public class DBImage
{
  @Parameter(required=true)
  private Image image;

  @Inject
  private ComponentResources resources;

  boolean beginRender(MarkupWriter writer)
  {
    writer.element("img", "src", image.toClientURL(), "class", "db-image");

    resources.renderInformalParameters(writer);

    writer.end();

    return false;
  }
}

Why do I get

...

java.lang.LinkageError when I invoke public methods of my page classes?

In Tapestry, there are always two versions of page (or component) classes. The first version is the version loaded by standard class loader: the simple POJO version that you wrote.

...

In a Tapestry application, most application classes, including your services, are loaded from the middle class loader. When a page or component is passed as a parameter to a service, a failure occurs
(how it is reported varies in different JDK releases) because of the class mismatch.

The solution is to define an interface with the methods that the service will invoke on the page or component instance. The service will expect an object implementing the interface (and doesn't care what class loader loaded
the implementing class).

Just be sure to put the interface class in a non-controlled package, such as you root-package (and not root-package.pages).