private JFieldVar addAdditionalPropertiesField(JDefinedClass jclass, JType propertyType) {
JClass propertiesMapType = jclass.owner().ref(Map.class);
propertiesMapType = propertiesMapType.narrow(jclass.owner().ref(String.class), propertyType.boxify());
JClass propertiesMapImplType = jclass.owner().ref(HashMap.class);
propertiesMapImplType = propertiesMapImplType.narrow(jclass.owner().ref(String.class), propertyType.boxify());
JFieldVar field = jclass.field(JMod.PRIVATE, propertiesMapType, "additionalProperties");
ruleFactory.getAnnotator().additionalPropertiesField(field, jclass, "additionalProperties");