ElasticSearch Match_All_query(JAVA)

public List<Map<String,Object>> HighLevelClientQuery(){
        List<Map<String,Object>> rules = new ArrayList<Map<String,Object>>();
        String indexName = "indexName";
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(
                QueryBuilders.matchAllQuery()
        );
        searchSourceBuilder.size(1000);
        try {
            SearchRequest request = new SearchRequest(indexName);
            request.source(searchSourceBuilder);
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            SearchHits searchHits = response.getHits();
            for(SearchHit hit : searchHits){
                Map<String, Object> result = hit.getSourceAsMap();
                rules.add(result);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return rules;
    }