apache/hadoop · error · IllegalArgumentException

key length must be > 0

Error message

key length must be > 0

What it means

Error "key length must be > 0" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/bloom/HashFunction.java:114

      throw new IllegalArgumentException("hashType must be known");
  }

  /** Clears <i>this</i> hash function. A NOOP */
  public void clear() {
  }

  /**
   * Hashes a specified key into several integers.
   * @param k The specified key.
   * @return The array of hashed values.
   */
  public int[] hash(Key k){
      byte[] b = k.getBytes();
      if (b == null) {
        throw new NullPointerException("buffer reference is null");
      }
      if (b.length == 0) {
        throw new IllegalArgumentException("key length must be > 0");
      }
      int[] result = new int[nbHash];
      for (int i = 0, initval = 0; i < nbHash; i++) {
	  initval = hashFunction.hash(b, initval);
	  result[i] = Math.abs(initval % maxValue);
      }
      return result;
  }
}

View on GitHub (pinned to 2add963021)

Solutions

1. The key to hash is empty. Provide a key with length > 0 before calling hash().

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/bloom/HashFunction.java:114 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/5f669c1a6fab9761. Report an issue: GitHub.