code: public String deleteScrolls(String [] scrollIds) throws ElasticSearchException{
  		if(scrollIds == null || scrollIds.length == 0)
  			return null;
  		if(!client.isV1()) {
  			StringBuilder entity = new StringBuilder();
  			entity.append("{\"scroll_id\" : [");
  			for (int i = 0; i < scrollIds.length; i++) {
  				String scrollId = scrollIds[i];
  				if (i > 0)
  					entity.append(",");
  				entity.append("\"").append(scrollId).append("\"");
  			}
  			entity.append("]}");
  			String result = this.client.executeHttp("_search/scroll", entity.toString(), ClientUtil.HTTP_DELETE);
  			return result;
  		}
  		else{
  //			for (int i = 0; i < scrollIds.length; i++) {
  //				String scrollId = scrollIds[i];
  //				this.client.executeHttp("_search/scroll?scroll_id="+scrollId, ClientUtil.HTTP_DELETE);
  //			}
  
  			if(logger.isTraceEnabled()){
  				logger.trace(new StringBuilder().append("Elasticsearch ").append(client.getEsVersion() )
  						.append( " do not support delete scrollId.").toString());
  			}
  			return "";
  		}
  	}
docs: 清理scrollId
  @param scrollIds
  @return
  @throws ElasticSearchException