SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

HighlightBuilder highlightBuilder = new HighlightBuilder(); 

HighlightBuilder.Field highlightTitle =

        new HighlightBuilder.Field("title"); 

highlightTitle.highlighterType("unified");  

highlightBuilder.field(highlightTitle);  

HighlightBuilder.Field highlightUser = new HighlightBuilder.Field("user");

highlightBuilder.field(highlightUser);

searchSourceBuilder.highlighter(highlightBuilder);