title: RedisSystemException: Unknown redis exception; nested exception is java.lang.NullPointerException
body: <p>Currently, i'm trying to learn spring data redis </p>
  
  <p>I've create some test project and successfully insert the data, however i got an issue when using pipeline command</p>
  
  <p>this is my config file : </p>
  
  <pre><code>public RedisTemplate&lt;String, String&gt; redisTemplate( JedisConnectionFactory jedisConnectionFactory) {
          RedisTemplate&lt;String, String&gt; redisTemplate = new RedisTemplate&lt;&gt;();
          redisTemplate.setConnectionFactory(jedisConnectionFactory);
          redisTemplate.setEnableTransactionSupport(true);
          redisTemplate.setKeySerializer(new StringRedisSerializer());
          redisTemplate.setValueSerializer(new StringRedisSerializer());
          return redisTemplate;
      }
  </code></pre>
  
  <p>and my repositoy :</p>
  
  <pre><code>    @Repository
      public class PaymentDetailRepoImpl implements PaymentDetailRepo {
  
  
          @Autowired RedisTemplate&lt;String, String&gt; redisTemplate;
  
          private ValueOperations&lt;String, String&gt; operation;
  
      @PostConstruct
      private void init() {
          operation = redisTemplate.opsForValue();
      }
  
          @Override
              public void saveMulti(List&lt;Payment&gt; listModel) {
                  this.redisTemplate.executePipelined(new RedisCallback&lt;Object&gt;() {
                      @Override
                      public Object doInRedis(RedisConnection connection) throws DataAccessException {
                          StringRedisConnection stringRedisConn = (StringRedisConnection)connection;
                          listModel.forEach(model -&gt; {
                              operation.set(model.getUser(), model.getTotal());
                          });
                          return null;
                      }
  
                  });
              }
  </code></pre>
  
  <p>the data was successfully import into redis but at the end of transaction i got following error :</p>
  
  <pre><code>org.springframework.data.redis.RedisSystemException: Unknown redis exception; nested exception is java.lang.NullPointerException
  </code></pre>
  
  <p>cause by:</p>
  
  <pre><code>by: java.lang.NullPointerException: null
      at redis.clients.jedis.Transaction.exec(Transaction.java:54)
      at org.springframework.data.redis.connection.jedis.JedisConnection.exec(JedisConnection.java:558)
  </code></pre>
  
  <p>do you have any idea why this error occured?</p>