What means this Exception?

Question

I try to test a code and got the Exception below:

The component(s) below failed to render. Possible reasons could be that: 1) you have added a component in code but forgot to reference it in the markup (thus the component will never be rendered), 2) if your components were added in a parent container then make sure the markup for the child container includes them in .

I don't know what to do now.

Answer 1

This error means that you have added a component in your Java code, e.g.:

add(new Label("someId", "Some text"));

but you forgot to add wicket:id="someId" to the corresponding HTML template.

So, Wicket says: I have a component in the Java component tree that I have no idea where and how to render.