question: gets the value of the relation 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 relation property . for example , to add a new item , do as follows : getrelation . add newitem ; objects of the following type s are allowed in the list relation concode_field_sep List<TRAJECTOR> trajector concode_elem_sep List<SPATIALINDICATOR> spatialindicator concode_elem_sep String id concode_elem_sep List<LANDMARK> landmark concode_elem_sep CONTENT content concode_elem_sep List<RELATION> relation concode_field_sep void setContent concode_elem_sep CONTENT getCONTENT concode_elem_sep List<Containable> getLANDMARK concode_elem_sep String getContent concode_elem_sep void setId concode_elem_sep String getId concode_elem_sep List<Containable> getTRAJECTOR concode_elem_sep List<Containable> getSPATIALINDICATOR concode_elem_sep void setCONTENT
target: List < RELATION > function ( ) { if ( relation == null ) { relation = new ArrayList < RELATION > ( ) ; } return this . relation ; }