EDIT

import com.vaadin.data.Property;

import com.vaadin.data.Property.ValueChangeListener;

import com.vaadin.data.Validator.InvalidValueException;

import com.vaadin.shared.ui.MarginInfo;

import com.vaadin.spring.annotation.SpringComponent;

import com.vaadin.ui.AbstractField;

                        return value == null || value.isEmpty() ;

                    }

        };

        nomStatusCollectionField.getLayout().setSpacing(false);