BulkIndex批量对1000条数据建立索引

每次运行批量对1000条数据建立索引前，都删掉原来的索引！结果每次运行完查询，每次的生成的索引条数都不一样，而且每次都没有达到1000条！bulkResponse.hasFailures()这个也没有说有错误。多次运行的时候经常还会出现空指针异常，如下：Exception in thread "main" java.lang.NullPointerException
    at org.elasticsearch.action.bulk.BulkRequest.validate(BulkRequest.java:496)
    at org.elasticsearch.action.TransportActionNodeProxy.execute(TransportActionNodeProxy.java:46)
    at org.elasticsearch.client.transport.support.TransportProxyClient$1.doWithNode(TransportProxyClient.java:58)
    at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:212)
    at org.elasticsearch.client.transport.support.TransportProxyClient.execute(TransportProxyClient.java:55)
    at org.elasticsearch.client.transport.TransportClient.doExecute(TransportClient.java:288)
    at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:359)
    at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:86)
    at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:56)
    at org.elasticsearch.action.ActionRequestBuilder.get(ActionRequestBuilder.java:64)
望大神们，能指点一下？