This Callback class
represents a request for the username or other text that identifies
the user to be authenticated. An interactive
CallbackHandler should call getPrompt(
) and
getdefaultName( ) and should display the returned
prompt and optionally, the returned default name to the user. When
the user has entered a name (or accepted the default name) the
handler should pass the user's input to
setName( ).

public class NameCallback implements Callback, Serializable {
// Public Constructors
public NameCallback(String prompt);
public NameCallback(String prompt, String defaultName);
// Public Instance Methods
public String getDefaultName( );
public String getName( );
public String getPrompt( );
public void setName(String name);
}