title: Filtering a Kafka stream against a huge list of elements
body: <p>I have a very specific requirement where in I am consuming records from a Kafka topic. The records read from this topic contains individual bank transaction of cusomers. Obviously it has the bank account number in it.
  Also I have a database table in Oracle containing account numbers of the customers. This table has around 50k records which are the accounts subscribed for a particular service.
  The requirement is that I want to have a filter on the records being streamed from Kafka topic such that it should give me only those records from the topic whose account number matches the 50k account numbers from the above table.</p>
  
  <p>NOTE: I am using Java 8 for this.</p>
  
  <p>Hope I have provided enough information for the scenario I am trying to explain. </p>