redis/jedis · error · IllegalArgumentException

HashImport fields must not contain null

Error message

HashImport fields must not contain null

What it means

HashImport.of(String...) throws IllegalArgumentException if any individual field in the varargs array is null. Each field is encoded via SafeEncoder.encode, which cannot accept null, and a null field would corrupt the import template.

Solutions

1. Filter nulls before the call: fields list.removeIf(Objects::isNull) or use a stream filter.
2. Replace null entries with sensible defaults if a value is genuinely required.
3. Validate caller-side that every element is non-null before constructing the HashImport.

Example fix

// before
HashImport t = HashImport.of(rawFields); // rawFields may contain nulls
// after
String[] clean = Arrays.stream(rawFields).filter(Objects::nonNull).toArray(String[]::new);
HashImport t = HashImport.of(clean);

boolean noNulls = Arrays.stream(fields).noneMatch(Objects::isNull);
if (!noNulls) { /* filter or reject before HashImport.of */ }

boolean allNonNull(String[] a) { return a != null && Arrays.stream(a).allMatch(Objects::nonNull); }

try {
  HashImport t = HashImport.of(fields);
} catch (IllegalArgumentException e) {
  log.warn("Null hash field rejected: {}", e.getMessage());
}

When it happens

Trigger: Calling HashImport.of("a", null, "c"); passing a String[] populated from a sparse source (e.g. a list with nulls from a database or JSON array with null entries).

Common situations: Deserialized JSON arrays containing nulls; SQL query results with NULL columns collected into arrays; Optional mishandling producing null elements in a dynamically built list.

Related errors

• Driver version must not be null
• HashImport fields must be non-null and non-empty
• HashImport fields must not contain empty names
• HashImport fields must not contain duplicates
• Path cannot be null.

AI-assisted analysis of redis/jedis@6dac31d4c2 (2026-09-08). Data as JSON: /api/errors/d7e6071d9115c4fc. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/redis/clients/jedis/HashImport.java:79

    this.name = name;
    this.fields = fields;
  }

  /**
   * Creates a template from the given {@link String} field names.
   * @param fields the ordered field names; must be non-empty with no {@code null}, empty, or
   *          duplicate entries
   * @return a new, uniquely named template
   * @since 8.0
   */
  public static HashImport of(String... fields) {
    if (fields == null || fields.length == 0) {
      throw new IllegalArgumentException("HashImport fields must be non-null and non-empty");
    }
    List<byte[]> encoded = new ArrayList<>(fields.length);
    for (String field : fields) {
      if (field == null) {
        throw new IllegalArgumentException("HashImport fields must not contain null");
      }
      encoded.add(SafeEncoder.encode(field));
    }
    return build(encoded);
  }

  /**
   * Creates a template from the given binary field names.
   * @param fields the ordered field names; must be non-empty with no {@code null}, empty, or
   *          duplicate entries (duplicates are compared by content).
   * @return a new, uniquely named template
   * @since 8.0
   */
  public static HashImport of(byte[]... fields) {
    if (fields == null || fields.length == 0) {
      throw new IllegalArgumentException("HashImport fields must be non-null and non-empty");
    }
    List<byte[]> copy = new ArrayList<>(fields.length);

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