redis/jedis · error · NullPointerException

A null argument cannot be sent to Redis.

Error message

A null argument cannot be sent to Redis.

What it means

RediSearchUtil.toStringMap converts a Map<String,Object> into a flat String map for RediSearch commands. A NullPointerException is thrown when any key or value in the input map is null, since the Redis protocol cannot transmit null arguments.

Solutions

1. Sanitize the map before the call: remove entries with null keys or values
2. Substitute sensible defaults for null values (e.g. empty string) if the semantics allow
3. If a null signals 'not present', omit the attribute rather than sending it

Example fix

// before
Map<String,String> attrs = RediSearchUtil.toStringMap(input, true);
// after
input.values().removeIf(Objects::isNull);
Map<String,String> attrs = RediSearchUtil.toStringMap(input, true);

Map<String,Object> safe = new HashMap<>();
input.forEach((k, v) -> { if (k != null && v != null) safe.put(k, v); });
Map<String,String> out = RediSearchUtil.toStringMap(safe, stringEscape);

When it happens

Trigger: Calling toStringMap with a map containing null keys or null values, e.g. attributes built from incomplete user input or Optional.orElse(null) patterns.

Common situations: Document/attribute maps assembled from JSON deserialization where fields are missing; search filter params with unset values; dynamic metadata maps with absent keys.

Related errors

• Setting null as field attribute is not allowed.
• Attribute for this field is already set.
• Unrecognized header
• DIALECT=0 cannot be set.
• DIALECT=0 cannot be set.

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/b835b586bed5777d. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/search/RediSearchUtil.java:41

  public static Map<String, String> toStringMap(Map<String, Object> input) {
    return toStringMap(input, false);
  }

  /**
   * Jedis' {@code hset} methods do not support {@link Object}s as values. This method eases process
   * of converting a {@link Map} with Objects as values so that the returning Map can be set to a
   * {@code hset} method.
   * @param input map with object value
   * @param stringEscape whether to escape the String objects
   * @return map with string value
   */
  public static Map<String, String> toStringMap(Map<String, Object> input, boolean stringEscape) {
    Map<String, String> output = new HashMap<>(input.size());
    for (Map.Entry<String, Object> entry : input.entrySet()) {
      String key = entry.getKey();
      Object obj = entry.getValue();
      if (key == null || obj == null) {
        throw new NullPointerException("A null argument cannot be sent to Redis.");
      }
      String str;
      if (obj instanceof byte[]) {
        str = SafeEncoder.encode((byte[]) obj);
      } else if (obj instanceof redis.clients.jedis.GeoCoordinate) {
        redis.clients.jedis.GeoCoordinate geo = (redis.clients.jedis.GeoCoordinate) obj;
        str = geo.getLongitude() + "," + geo.getLatitude();
      } else if (obj instanceof String) {
        str = stringEscape ? escape((String) obj) : (String) obj;
      } else {
        str = String.valueOf(obj);
      }
      output.put(key, str);
    }
    return output;
  }

  /**

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