Query Builders unable to build queries.

QueryBuilders not working

package nachiket.trial;

import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.Client;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.CustomScoreQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;

public class Tryout {
	
	public static void main(String args[])
	{
		BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
		boolQueryBuilder.boost(0);
		boolQueryBuilder.must( QueryBuilders.boostingQuery().positive( QueryBuilders.termQuery("a1", "b1")  ).negative( QueryBuilders.termQuery("c1", "d1") ).negativeBoost(0) );
		boolQueryBuilder.must( QueryBuilders.boostingQuery().positive( QueryBuilders.termQuery("a2", "b2")  ).negative( QueryBuilders.termQuery("c2", "d2") ).negativeBoost(1) );
		CustomScoreQueryBuilder customScoreQueryBuilder = QueryBuilders.customScoreQuery( boolQueryBuilder ).script("scoring").lang("native").params(null);
		CustomScoreQueryBuilder custom = QueryBuilders.customScoreQuery( QueryBuilders.customScoreQuery( boolQueryBuilder ).script("_score") );
		Client client = new TransportClient().addTransportAddress(new InetSocketTransportAddress("192.168.1.8",9300));
		System.out.println(custom.toString());
//		System.out.println( custom.buildAsUnsafeBytes() );
		SearchResponse response = client.prepareSearch("twitter").setTypes("doc")
		.setQuery( QueryBuilders.boolQuery().must( QueryBuilders.termQuery("a","b") ) 
		.must( QueryBuilders.boostingQuery().positive( QueryBuilders.termQuery("a", "v") ).negative( QueryBuilders.termQuery("c", "d") ).negativeBoost(0) )		
		).execute()
		.actionGet();
	}

}




Exception in thread "main" org.elasticsearch.search.builder.SearchSourceBuilderException: Failed to build search source
	at org.elasticsearch.search.builder.SearchSourceBuilder.buildAsUnsafeBytes(SearchSourceBuilder.java:389)
	at org.elasticsearch.action.search.SearchRequest.source(SearchRequest.java:259)
	at org.elasticsearch.client.action.search.SearchRequestBuilder.doExecute(SearchRequestBuilder.java:574)
	at org.elasticsearch.client.action.support.BaseRequestBuilder.execute(BaseRequestBuilder.java:56)
	at org.elasticsearch.client.action.support.BaseRequestBuilder.execute(BaseRequestBuilder.java:51)
	at nachiket.trial.Tryout.main(Tryout.java:28)
Caused by: org.elasticsearch.common.jackson.JsonGenerationException: Current context not an ARRAY but OBJECT
	at org.elasticsearch.common.jackson.impl.JsonGeneratorBase._reportError(JsonGeneratorBase.java:480)
	at org.elasticsearch.common.jackson.smile.SmileGenerator.writeEndArray(SmileGenerator.java:561)
	at org.elasticsearch.common.xcontent.json.JsonXContentGenerator.writeEndArray(JsonXContentGenerator.java:58)
	at org.elasticsearch.common.xcontent.XContentBuilder.endArray(XContentBuilder.java:226)
	at org.elasticsearch.index.query.BoolQueryBuilder.doXArrayContent(BoolQueryBuilder.java:146)
	at org.elasticsearch.index.query.BoolQueryBuilder.doXContent(BoolQueryBuilder.java:119)
	at org.elasticsearch.index.query.BaseQueryBuilder.toXContent(BaseQueryBuilder.java:64)
	at org.elasticsearch.search.builder.SearchSourceBuilder.toXContent(SearchSourceBuilder.java:420)
	at org.elasticsearch.search.builder.SearchSourceBuilder.buildAsUnsafeBytes(SearchSourceBuilder.java:386)
	... 5 more