Use LinkedHashMap instead of HashMap for Map outputs

[mp911de]

The response maps use the HashMap implementation to transport map data structures. A HashMap has a random order and does not preserve the Redis ordering. Switch therefore to a LinkedHashMap.

Motivation: A LinkedHashMap preserves the order of elements whereas a HashMap maintains a "random order". The order of Redis hash values depends on the order of insertion. Users might want to preserve that order and that's the reason why to use a LinkedHashMap.

References:

• http://stackoverflow.com/questions/26414757/linkedhashmap-behaviour-with-redis-hashes
• http://stackoverflow.com/questions/31767537/jedis-hmset-map-insertion-order