ERROR - com.mongodb.BulkWriteException - Possible Causes of BulkWriteException

Exception Thrown By:Cause
ClassMethod
BulkWriteOperation [public BulkWriteResult execute() if the write failed due to some
other failure specific to the write command. 
BulkWriteOperation public BulkWriteResult execute(WriteConcern writeConcern) if the write failed due to some
other failure specific to the write command.