question: protected Map < String , Set < String > > filterQueryParamsByKey ( QueryParamsParserContext context , String queryKey ) { Map < String , Set < String > > filteredQueryParams = new HashMap < > ( ) ; for ( String paramName : context . getParameterNames ( ) ) { if ( paramName . startsWith ( queryKey ) ) { filteredQueryParams . put ( paramName , context . getParameterValue ( paramName ) ) ; } } return filteredQueryParams ; }
target:  Filters provided query params to one starting with provided string key