apache/hadoop · error · IllegalArgumentException

nbHash must be > 0

Error message

nbHash must be > 0

What it means

Error "nbHash 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:89

  /** Hashing algorithm to use. */
  private Hash hashFunction;
  
  /**
   * Constructor.
   * <p>
   * Builds a hash function that must obey to a given maximum number of returned values and a highest value.
   * @param maxValue The maximum highest returned value.
   * @param nbHash The number of resulting hashed values.
   * @param hashType type of the hashing function (see {@link Hash}).
   */
  public HashFunction(int maxValue, int nbHash, int hashType) {
    if (maxValue <= 0) {
      throw new IllegalArgumentException("maxValue must be > 0");
    }
    
    if (nbHash <= 0) {
      throw new IllegalArgumentException("nbHash must be > 0");
    }

    this.maxValue = maxValue;
    this.nbHash = nbHash;
    this.hashFunction = Hash.getInstance(hashType);
    if (this.hashFunction == null)
      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.
   */

View on GitHub (pinned to 2add963021)

Solutions

1. nbHash must be positive. Construct the HashFunction with at least one hash function.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/bloom/HashFunction.java:89 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/f614a04a2d075cf8. Report an issue: GitHub.