I want to map exactly same reference_link by java.
Well i found the solution,what i have done is :
other code above (to start from beginning):-
.startObject(tags.getTitle()).field("type", "string")
.startObject("fields").startObject("raw")
.field("type", "string")
.field("analyzer", "case_insensitive_sort").endObject()
.endObject().endObject()
then end code.