method will add a value to a existing key or create a key and a value to amp concode_field_sep Map<String,List<String>> map concode_field_sep void readFile concode_elem_sep ArrayList<String> searchMap concode_elem_sep void main concode_elem_sep boolean remove
void function ( Map < KEY , List < VALUE >> arg0 , KEY arg1 , VALUE arg2 ) { arg0 . compute ( arg1 , ( s , strings ) -> strings == null ? new ArrayList < > ( ) : strings ) . add ( arg2 ) ; }