How to include JSF input field label in Bean Validation error message?

How can I show the field label in a JSF error message when bean validation is used?

<h:messages/>
<h:inputText label="Username" value="#{myBean.username}" />
...   

public class MyBean {
    @NotNull
    private String username;
    ...
}

If no user name is submitted only "Must not be null" is shown and there is no field reference.

To display the concerned component's label in the error message define a new value for the property javax.faces.validator.BeanValidator.MESSAGE in a <message-bundle> of the application like this:

javax.faces.validator.BeanValidator.MESSAGE={1}: {0}

The placeholder {0} refers to the error message as created by the Bean Validation runtime, {1} refers to the component label. More information can be found in the JSF 2.0 spec section 3.5.6.3.

When using Faces 4.0 or newer, then of course use jakarta.* instead of javax.*, see also Faces 4.0 spec section 3.5.6.4:

jakarta.faces.validator.BeanValidator.MESSAGE={1}: {0}