How is it going?
I am just wondering if it is possible to communicate from java application with database/server.
Are there any java clients around open-source to have a look at?
Yes, jedis is one of the more popular redis library that you can use within your Java application.
If you are interested, RedisLabs provides a free Jedis course in their Redis University.
This is a good quick tutorial to get you started as well: https://www.tutorialspoint.com/redis/redis_java.htm
Of course you can use java query on Redis, as by using jedis you can do that easily as it help to communicate with database more easily