apache/beam · error · IllegalArgumentException

Value cannot be null or have 0 elements

Error message

Value cannot be null or have 0 elements

What it means

OrderedCode.writeTrailingBytes appends raw trailing bytes to the ordered encoding. It rejects null or zero-length arrays with IllegalArgumentException because a zero-length trailing segment makes the encoding ambiguous/unreadable by readTrailingBytes.

Solutions

1. Guard the call site: skip writeTrailingBytes when the byte array is null or empty.
2. If a terminator is needed for empty payloads, write a sentinel value (e.g. a single 0x00 byte) instead.
3. Catch IllegalArgumentException if empty input is a legitimate condition in your encoding flow.

Example fix

// before
oc.writeTrailingBytes(suffix);
// after
if (suffix != null && suffix.length > 0) {
  oc.writeTrailingBytes(suffix);
}

if (value == null || value.length == 0) {
  // skip write or substitute sentinel
}

boolean writableTrailing(byte[] v) { return v != null && v.length > 0; }

try { oc.writeTrailingBytes(value); } catch (IllegalArgumentException e) { /* skip empty segment */ }

When it happens

Trigger: Calling writeTrailingBytes(null) or writeTrailingBytes(new byte[0]) on an OrderedCode instance mid-encoding.

Common situations: Encoding a key component derived from a possibly-empty payload (e.g. empty suffix bytes from a parsed key) without checking length first.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Could not encode provided windows with the provided window…
• Empty argument value is only allowed for String, String…
• Invalid encoded byte array
• 'keyField' property cannot be null.
• Text payload is not valid UTF-8.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/fb23e0af04e35210. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/OrderedCode.java:361

   *
   * @see #readInfinityDecreasing()
   */
  public void writeInfinityDecreasing() {
    writeTrailingBytes(INFINITY_ENCODED_DECREASING);
  }

  /**
   * Appends the byte array item to its internal encoded byte array store. This is used for the last
   * item and is not encoded.
   *
   * <p>It stores the input array in the store, so the input array 'value' should not be modified.
   *
   * @param value bytes to be written.
   * @see #readTrailingBytes()
   */
  public void writeTrailingBytes(byte[] value) {
    if ((value == null) || (value.length == 0)) {
      throw new IllegalArgumentException("Value cannot be null or have 0 elements");
    }

    encodedArrays.add(value);
  }

  /**
   * Returns the next byte array item from its encoded byte array store and removes the item from
   * the store.
   *
   * @see #writeBytes(byte[])
   */
  public byte[] readBytes() {
    return readBytes(false);
  }

  public byte[] readBytesDecreasing() {
    return readBytes(true);
  }

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