question: private boolean writeReference ( Object value , NodeMap node ) { String name = get ( value ) ; int size = size ( ) ; if ( name != null ) { node . put ( refer , name ) ; return true ; } String unique = String . valueOf ( size ) ; node . put ( mark , unique ) ; put ( value , unique ) ; return false ; }
target:  This is used to write the XML element attributes representing the serialized object instance. If the object has already been serialized to the XML document then a reference attribute is inserted and this returns true, if not, then this will write a unique identity marker attribute and return false.