TransactionOpsExample.java

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.Transaction;

import java.util.List;

public class TransactionOpsExample {

    public static void main(String[] args) throws Exception {
        JedisPool pool = new JedisPool(new JedisPoolConfig(), "localhost");
        Jedis jedis = null;
        try {
            jedis = pool.getResource();
            jedis.hset("account:1", "deposit", "100");
            String acc_details = jedis.hget("account:1", "deposit").toString();
            System.out.println("Before watch, acc_deposit=" + acc_details);
            System.out.println("Watching account:1 key");
            jedis.watch("account:1");
            Transaction t = jedis.multi();
            System.out.println("Initiated transaction block");
            t.hset("account:1", "deposit", "150");
            System.out.println("increasing deposit value to 150");
            Thread.sleep(5000);
            //create new thread and increase deposit value outside of transaction queued thread
            new Thread(() -> {
                System.out.println("New thread outside of transaction block updating deposit value to 120");
                Jedis jedis1 = new JedisPool(new JedisPoolConfig(), "localhost").getResource();
                jedis1.hset("account:1", "deposit", "120");
            }).start();
            //execute transaction thread
            List<Object> objectList = t.exec();
            //returns null
            if(objectList!= null) {
                System.out.println(jedis.hgetAll("account:1").toString());
                for (Object obj : objectList) {
                    System.out.println(obj.toString());
                }
            }else{
                System.out.println("Transaction returned null");
                System.out.println("final account deposit");
                System.out.println(jedis.hgetAll("account:1").toString());
            }

        } finally {
            if (jedis != null) {
                jedis.close();
            }
        }
        /// ... when closing your application:
        pool.destroy();
    }
}