1. Kafka  Messaging Server - Distributed (Durable) Messaging Server [http://kafka.apache.org/]
     2. Spring Boot - Java Microframework [http://projects.spring.io/spring-boot/]
     3. NATS Messaging Server  - High Performance Messaging Server [http://nats.io/]
     4. Crate DB  - Scalable DB based on ElasticSearch [https://crate.io/]
     5. These technologies can be potentially good candidates for distributed/micro-services based systems

     [Rest Request (Browser/Postman/Rest Client)] 
             => [Rest Controller (Spring Boot)]
             => [NATS Publisher sends pay-load to NATS messaging server (Spring Bean)]
             => [NATS Subscriber processes the message (Spring Bean) & invokes Kafka Publisher (Spring Bean) ]
             => [Kafka Publisher publishes the message to a Kafka Topic (Spring Bean)
             => [Kafka Consumer then persists the message to CRATE database (Spring Bean)]

     1. Kafka serves as a durable-cum-distributed messaging server
     2. Spring Boot serves as Java -microframework  for Restful APIs.
     3. NATS serves as a high-performance in-memory/distributed messaging server
              - Can be used for loadbalancing
              - Can be used for Service Discovery
              - Auto-prunes unresponsive/slow clients
              - Very,very fast - IO 
              - Tiny footprint, suitable for microservices-style artchitectures
              - And lots more, please check their website
              
     4. Crate DB - Scalable database based on elastic search
                 - Brings SQL style interface to NoSQL storage engine
                 - Scalable & Distributed
                 - Can be used in places where Cassandra & Elastic search were used
                 - Very new, stability needs to be proven yet
                 - Looks promising