Given a model like

@javax.enterprise.inject.Model
public class Model
{
private String data;

public String getData()

{ return data; }

public void setData(String data)

{ System.out.println("set data to " + data); this.data = data; }

}

and a view like

<h:form>
<h:inputText id="field" value="#

{model.data}

"/>
<h:commandButton value="!"/>
</h:form>

an empty value is submitted even with

<context-param>
<param-name>javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL</param-name>
<param-value>true</param-value>
</context-param>

Debugging the application shows that the emptyStringIsNull of the component is true.

even with a @FacesConverter(forClass=String.class) which is correctly run and doing a setSubmittedValue(null), the model still sees a "" instead of a null

Tested to work correctly on a GF 3.0.1