question: gets the value of the extension property . this accessor method returns a reference to the live list , not a snapshot . therefore any modification you make to the returned list will be present inside the jaxb object . this is why there is not a set method for the extension property . for example , to add a new item , do as follows : getextension . add newitem ; objects of the following type s are allowed in the list extensiontype concode_field_sep List<ExtensionType> extension concode_elem_sep NymType nym concode_elem_sep ExtensionOnlyType writtenConsent concode_elem_sep PhysicalVerification physicalVerification concode_elem_sep GoverningAgreementsType governingAgreements concode_field_sep void setWrittenConsent concode_elem_sep GoverningAgreementsType getGoverningAgreements concode_elem_sep void setGoverningAgreements concode_elem_sep void setPhysicalVerification concode_elem_sep void setNym concode_elem_sep NymType getNym concode_elem_sep ExtensionOnlyType getWrittenConsent concode_elem_sep PhysicalVerification getPhysicalVerification
target: List < ExtensionType > function ( ) { if ( extension == null ) { extension = new ArrayList < ExtensionType > ( ) ; } return this . extension ; }