IndexRequest iRequest = new IndexRequest(LoadBalancerVip+"9" , "_doc");
iRequest.source(flattenedJson,XContentType.JSON);
This innocent XContentType.Json cannot insert more than 150 records neither it shows any bug try at your end.
JVM usage disk usage are normal. Once I remove XContentType.json it works perfectly fine.
Just incase if this helps someone
Data to try
{"A":true,"B":"BVALUE","name":"Joe","C":"#C:ID","Key":29,"MYAddress":"11.11.111.0","from":"google.com"}"
type or paste code here